Polycarbonate resin composition for sliding use and molded article using the resin composition
Provided is a polycarbonate-based resin composition for sliding use including 0.01 to 1 part by mass of an antioxidant with respect to 100 parts by mass of a polycarbonate-polyorganosiloxane copolymer which has structural units represented by a general formula (A) and structural units represented by a general formula (B), which contains a polyorganosiloxane block moiety containing the structural units represented by the general formula (B) at a content of 1 to 30 mass %, and which has an average repetition number of the structural units represented by the general formula (B) of 110 to 1000. The polycarbonate-based resin composition for sliding use has a specific structure having improved wear resistance, in particular, improved sliding property. Also provided is a molded article using the resin composition, and excellent in wear resistance and sliding property.
1. A molded article obtained by injection molding a polycarbonate-based resin composition comprising:
0.01 to 1 part by mass of an antioxidant with respect to 100 parts by mass of a polycarbonate-polyorganosiloxane copolymer which has at least one structural unit represented by formula (A)
and at least one structural unit represented by formula (B)
wherein
the polycarbonate-polyorganosiloxane copolymer comprises a polyorganosiloxane block moiety comprising the structural unit of the formula (B) at a content of 1 to 30 mass %,
the polycarbonate-polyorganosiloxane copolymer has an average repetition number of the structural unit of the formula (B) of 110 to 1000,
R 1 and R 2 each independently represent an alkyl or alkoxy group having 1 to 6 carbon atoms,
X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, —S—, —SO—, —SO 2 —, —O—, or —CO—,
R 3 and R 4 each independently represent a hydrogen atom, a halogen atom, or an alkyl or aryl group which may have a substituent,
a and b each represent an integer of 0 to 4, and
the molded article has a wear loss of 3 mm 3 or less, determined in conformity with JIS K7218 A method (Ring on Ring).
2. The molded article according to claim 1 , wherein the polycarbonate-polyorganosiloxane copolymer has a viscosity average molecular weight of 13,000 to 50,000.
3. The molded article according to claim 1 , further comprising 2 to 98 parts by mass of an aromatic polycarbonate with respect to 100 parts by mass of the polycarbonate-polyorganosiloxane copolymer.
4. The molded article according to claim 2 , further comprising 2 to 98 parts by mass of an aromatic polycarbonate with respect to 100 parts by mass of the polycarbonate-polyorganosiloxane copolymer.
5. The molded article according to claim 1 , wherein the polycarbonate-polyorganosiloxane copolymer has a viscosity average molecular weight of 15,000 to 30,000.
6. The molded article according to claim 1 , wherein the polycarbonate-polyorganosiloxane copolymer has a viscosity average molecular weight of 15,000 to 26,000.
7. The molded article according to claim 1 , comprising 0.01 to 0.5 parts by mass of the antioxidant with respect to 100 parts by mass of a polycarbonate-polyorganosiloxane copolymer.
8. The molded article according to claim 1 , wherein the molded article has a critical PV value of greater than 75 KPa·m/s, determined in conformity with JIS K7218 A method (Ring on Ring).