POLYCARBONATE RESIN COMPOSITION, METHOD FOR PRODUCING SAME AND MOLDED ARTICLE OF THIS RESIN COMPOSITION

1 . A polycarbonate resin composition comprising at least a polycarbonate resin (a) and a polycarbonate resin (b) having structural units different from the polycarbonate resin (a), which satisfies the following requirements:

(i) the pencil hardness of the polycarbonate resin (a) as specified by ISO 15184 is higher than the pencil hardness of the polycarbonate resin (b) as specified by ISO 15184;

(ii) the glass transition point Tg(a) of the polycarbonate resin (a) and the glass transition point Tg(b) of the polycarbonate resin (b) satisfy the relation of the following (Formula 1):

Tg ( b )−45° C.<( a )< Tg ( b )−10° C.  (Formula 1)

and

(iii) the pencil hardness of the polycarbonate resin composition as specified by ISO 15184 is higher by at least two ranks than the pencil hardness of the polycarbonate resin (b) as specified by ISO 15184.

2 . A polycarbonate resin composition comprising at least a polycarbonate resin (a) and a polycarbonate resin (b) having structural units different from the polycarbonate resin (a), which satisfies the following requirements:

(i) the pencil hardness of the polycarbonate resin (a) as specified by ISO 15184 is higher than the pencil hardness of the polycarbonate resin (b) as specified by ISO 15184; and

(ii) the ratio of the intrinsic viscosity [η](a) of the polycarbonate resin (a) to the intrinsic viscosity [η](b) of the polycarbonate resin (b), [η](a)/[η](b), is at least 0.1 and at most 0.65.

3 . The polycarbonate resin composition according to claim 1 , wherein the ratio of the viscosity average molecular weight Mv(a) of the polycarbonate resin (a) to the viscosity average molecular weight Mv(b) of the polycarbonate resin (b), Mv(a)/Mv(b), is at least 0.1 and at most 2.0.

4 . The polycarbonate resin composition according to claim 1 , wherein the weight ratio of the polycarbonate resin (a) to the polycarbonate resin (b) in the polycarbonate resin composition is within a range of from 1:99 to 45:55.

5 . The polycarbonate resin composition according to claim 1 , wherein the pencil hardness of the polycarbonate resin (a) as specified by ISO 15184 is at least F.

6 . The polycarbonate resin composition according to claim 1 , wherein the pencil hardness of the polycarbonate resin composition as specified by ISO 15184 is at least HB.

7 . The polycarbonate resin composition according to claim 1 , wherein the above Tg(a) and Tg(b) satisfy the relation of the following (Formula 2):

Tg ( b )−30° C.< Tg ( a )< Tg ( b )−15° C.  (Formula 2)

8 . The polycarbonate resin composition according to claim 1 , wherein the polycarbonate resin (a) is a polycarbonate resin having at least structural units derived from a compound represented by the following formula (1):

wherein each of R 1 and R 2 which are independent of each other, is a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, each of R 3 and R 4 which are independent of each other, is a hydrogen atom, a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, and X is a single bond, a carbonyl group, a substituted or non-substituted alkylidene group, an oxidized or non-oxidized sulfur atom, or an oxygen atom.

9 . The polycarbonate resin composition according to claim 1 , wherein the polycarbonate resin (a) is a polycarbonate resin having at least structural units derived from at least one compound selected from the group consisting of the following formulae (1a) to (1c):

10 . The polycarbonate resin composition according to claim 1 , wherein the polycarbonate resin (b) is a polycarbonate resin having mainly structural units derived from a compound represented by the following formula (2):

11 . The polycarbonate resin composition according to claim 1 , which has a yellowness index (YI) of at most 4.0.

12 . The polycarbonate resin composition according to claim 1 , which further contains a flame retardant.

13 . A method for producing the polycarbonate resin composition as defined in claim 1 , which comprises melt-kneading the polycarbonate resin (a) and the polycarbonate resin (b).

14 . A method for producing the polycarbonate resin composition as defined in claim 1 , which comprises dry-blending the polycarbonate resin (a) and the polycarbonate resin (b).

15 . An injection-molded article, which is obtained by injection-molding the polycarbonate resin composition as defined in claim 1 .

16 . An extruded article, which is obtained by extruding the polycarbonate resin composition as defined in claim 1 .

17 . The extruded article according to claim 16 , which is a sheet or a film.

18 . A molded article of polycarbonate resin, comprising the polycarbonate resin composition as defined in claim 8 , wherein the ratio of the content [S] of the structural units (a) derived from a compound represented by the following formula (1) on the surface of the molded article of polycarbonate resin to the content [T] in the entire molded article of polycarbonate resin ([S]/[T]) is higher than 1.00 and at most 2.00:

wherein each of R 1 and R 2 which are independent of each other, is a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, each of R 3 and R 4 which are independent of each other, is a hydrogen atom, a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, and X is a single bond, a carbonyl group, a substituted or non-substituted alkylidene group, an oxidized or non-oxidized sulfur atom, or an oxygen atom.

19 . The molded article of polycarbonate resin according to claim 18 , which is an injection-molded article.

20 . The molded article of polycarbonate resin according to claim 18 , wherein the ratio of the content [S] of the structural units (a) on the surface of the molded article of polycarbonate resin to the content [T] in the entire molded article of polycarbonate resin ([S]/[T]) is at least 1.01 and at most 1.50.

21 . The molded article of polycarbonate resin according to claim 18 , wherein the pencil hardness on the surface of the molded article of polycarbonate resin as specified by ISO 15184 is at least HB.

22 . The molded article of polycarbonate resin according to claim 18 , wherein the structural units (a) are structural units derived from at least one compound selected from the group consisting of the following formulae (1a) to (1c):

23 . The molded article of polycarbonate resin according to claim 18 , wherein the polycarbonate resin (b) is a polycarbonate resin having mainly structural units (b) derived from a compound represented by the following formula (2):

24 . The molded article of polycarbonate resin according to claim 18 , which comprises at least a polycarbonate resin (a) having structural units (a) derived from a compound represented by the formula (1) and a polycarbonate resin (b) having structural units (b) different from the structural units (a) and having a structure different from the polycarbonate resin (a).

25 . The molded article of polycarbonate resin according to claim 18 , wherein the pencil hardness of the polycarbonate resin (a) as specified by ISO 15184 is higher than the pencil hardness of the polycarbonate resin (b) as specified by ISO 15184.

26 . The molded article of polycarbonate resin according to claim 18 , wherein the pencil hardness of the polycarbonate resin (a) as specified by ISO 15184 is at least F.

27 . The molded article of polycarbonate resin according to claim 18 , wherein the viscosity average molecular weight of the polycarbonate resin (a) is higher than the viscosity average molecular weight of the polycarbonate resin (b).

28 . A method for producing the molded article of polycarbonate resin as defined in claim 18 , comprising at least a polycarbonate resin (a) having structural units (a) derived from a compound represented by the following formula (1) and a polycarbonate resin (b) having structural units (b) different from the structural units (a), which comprises melt-kneading or dry-blending the polycarbonate resin (a) and the polycarbonate resin (b), followed by molding, wherein the viscosity average molecular weight of the polycarbonate resin (a) is higher than the viscosity average molecular weight of the polycarbonate resin (b):

wherein each of R 1 and R 2 which are independent of each other, is a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, each of R 3 and R 4 which are independent of each other, is a hydrogen atom, a substituted or non-substituted C 1-20 alkyl group or a substituted or non-substituted aryl group, and X is a single bond, a carbonyl group, a substituted or non-substituted alkylidene group, an oxidized or non-oxidized sulfur atom, or an oxygen atom.

29 . The method for producing the molded article of polycarbonate resin according to claim 28 , wherein the structural units (a) are structural units derived from at least one compound selected from the group consisting of the following formulae (1a) to (1c):

30 . The method for producing the molded article of polycarbonate resin according to claim 28 , wherein the structural units (b) are mainly structural units derived from a compound of the following formula (2):

31 . The method for producing the molded article of polycarbonate resin according to claim 28 , wherein the molding is injection-molding.