Production method of polycarbonate resin

1. A method for producing a polycarbonate resin, comprising performing polycondensation through a transesterification reaction with a catalyst and with a dihydroxy compound and a carbonic acid diester, and continuously feeding the produced polycarbonate resin to an extruder,

wherein

the polycarbonate is not solidified after the polycondensation and before being fed to the extruder,

the dihydroxy compound contains a dihydroxy compound having a moiety represented by the following formula (1) in a part of the structure,

the dihydroxy compound having a moiety represented by the following formula (1) contains a compound having a cyclic ether structure, and

the temperature at the time of feeding the polycarbonate resin to the extruder is from 180° C. to less than 250° C.:

CH 2 —O   (1)

with the proviso excluding the case where the moiety represented by formula (1) is a part of —CH 2 —O—H,

wherein a barrel constituting the extruder has a plurality of heaters and all of the heaters are set to a temperature of 100° C. to less than 250° C.

2. The method for producing a polycarbonate resin according to claim 1 , wherein the glass transition temperature of the polycarbonate resin obtained via the extruder is from 80° C. to less than 145° C.

3. The method for producing a polycarbonate resin according to claim 1 , wherein each of the heaters is set to a temperature not higher than the preset temperature of the heater adjacent to the polycarbonate resin feed side of the extruder.

4. The method for producing a polycarbonate resin according to claim 1 , wherein the polycarbonate resin produced by polycondensation through a transesterification reaction is fed in a molten state to the extruder.

5. The method for producing a polycarbonate resin according to claim 1 , wherein the extruder comprises a screw and wherein the screw of the extruder is composed of a plurality of elements, at least one of the elements is a kneading disc, and the total length of the kneading disc is 20% or less of the length of the screw as a whole.

6. The method for producing a polycarbonate resin according to claim 1 , wherein assuming that the weight of the resin extruded per hour from the extruder is W (kg/h) and the cross-sectional area of the barrel of the extruder is S (m 2 ), the following formula (5) is satisfied:

12000≦ W/S≦ 60000  (5).

7. The method for producing a polycarbonate resin according to claim 1 , wherein the reduced viscosity (η sp /c) of the polycarbonate resin obtained via the extruder, as measured in methylene chloride under the conditions of a concentration of 0.6 g/dL and a temperature of 20.0° C.±0.1° C., is from 0.3 to 1.2 dL/g.

8. The method for producing a polycarbonate resin according to claim 1 , wherein the glass transition temperature of the polycarbonate resin obtained via the extruder is from 90 to 140° C.

9. The method for producing a polycarbonate resin according to claim 1 , wherein the content of an aromatic monohydroxy compound contained in said polycarbonate resin obtained via said extruder is less than 0.1 wt %.

10. The method for producing a polycarbonate resin according to claim 1 , wherein the raw material monomers are filtered through a filter for raw material filtration before polycondensation.

11. The method for producing a polycarbonate resin according to claim 1 , wherein said extruder kneads a heat stabilizer.

12. The method for producing a polycarbonate resin according to claim 1 , wherein said catalyst is a compound of at least one metal selected from the group consisting of metals belonging to Group 2 of the long-form periodic table and lithium.

13. The method for producing a polycarbonate resin according to claim 1 , wherein the dihydroxy compound having a moiety represented by formula (1) is isosorbide.

14. The method for producing a polycarbonate resin according to claim 1 , wherein an alicyclic dihydroxy compound is further used as said dihydroxy compound.

15. A method for producing a polycarbonate resin pellet, comprising performing polycondensation through a transesterification reaction with a catalyst and with a dihydroxy compound and a carbonic acid diester, and continuously feeding the produced polycarbonate resin to an extruder, wherein

said polycarbonate is not solidified after said polycondensation and before being fed to said extruder

said dihydroxy compound contains at least a dihydroxy compound having a moiety represented by the following formula (1) in a part of the structure,

the glass transition temperature of the polycarbonate resin fed to said extruder is from 80° C. to less than 145° C., and

the temperature at the time of feeding said polycarbonate resin to said extruder is from 180° C. to less than 250° C.:

CH 2 —O   (1)

with the proviso excluding the case where the moiety represented by formula (1) is a part of —CH 2 —O—H,

wherein a barrel constituting the extruder has a plurality of heaters and all of the heaters are set to a temperature of 100° C. to less than 250° C.

16. A method for producing a polycarbonate resin, comprising performing polycondensation through a transesterification reaction with a catalyst and with a dihydroxy compound and a carbonic acid diester as raw material monomers, and continuously feeding the produced polycarbonate resin to an extruder, wherein

said polycarbonate is not solidified after said polycondensation and before being fed to said extruder,

said dihydroxy compound contains at least a dihydroxy compound having a moiety represented by the following formula (1) in a part of the structure,

the dihydroxy compound having a moiety represented by formula (1) is a compound having a cyclic ether structure,

the barrel constituting said extruder has a plurality of heaters, and all of the heaters is set to a temperature of 100° C. to less than 250° C.:

CH 2 —O   (1)

with the proviso excluding the case where the moiety represented by the formula (1) is a part of —CH 2 —O—H.

17. The method for producing a polycarbonate resin according to claim 1 , wherein

the glass transition temperature of the polycarbonate resin fed to said extruder is from 80° C. to less than 145° C., and

the glass transition temperature of the polycarbonate resin obtained from said extruder is from 80° C. to less than 145° C.