Polymer compositions having improved properties of thermal stability, color, and/or flow

1. A polymer composition comprising:

(A) at least one condensation polymer comprising at least one diol residue, and

(B) a stabilizer composition comprising:

(1) at least one primary antioxidant comprising at least one phenolic antioxidant; and

(2) at least one secondary antioxidant comprising at least one phosphite, and

(3) at least one chain extending agent;

wherein the at least one chain extending agent is selected from copolymers of glycidyl methacrylate with alkenes, copolymers of glycidyl methacrylate with alkenes and acrylic esters, copolymers of glycidyl methacrylate with alkenes and vinyl acetate, copolymers of glycidyl methacrylate and styrene, and wherein the at least one chain extending agent has an average of greater than or equal to 3 pendant epoxy groups per molecule;

wherein the weight ratio of chain extending agent to primary antioxidant is from 1:1 to 1:4; and

wherein the Δb* value for said polymer composition is less than 10 according to the L*, a* and b* color system of the CIE (International Commission on Illumination) after being heated for at least three hours at 200° C. or after being heated for at least twenty-four hours at 175° C.

2. The polymer composition according to claim 1 , wherein the at least one diol residue comprises 1,4-cyclohexanedimethanol (CHDM) residues.

3. The polymer composition according to claim 1 , wherein the at least one primary antioxidant is a hindered phenolic antioxidant.

4. The polymer composition according to claim 3 , wherein at least one hindered phenolic antioxidant is pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate.

5. The polymer composition according to claim 1 , wherein the phenolic antioxidant is present in an amount from 0.10 to 2.0 weight %, based on the total weight of the polymer composition equaling 100 weight %.

6. The polymer composition according to claim 1 , wherein the at least one phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite.

7. The polymer composition according to claim 1 , wherein the phosphite antioxidant is present in an amount from 0.10 weight % to 1 weight %, based on the total weight of the polymer composition.

8. The polymer composition according to claim 1 , wherein the weight ratio of phenolic antioxidant (1) to phosphite antioxidant (2) is from 1.1:1 to 3:1.

9. The polymer composition according to claim 1 , wherein the at least one chain extending agent has an average of 3 to 20 pendant epoxy groups per molecule.

10. The polymer composition according to claim 1 , wherein the chain extending agent comprises a copolymer of glycidyl methacrylate with styrene.

11. The polymer composition according to claim 1 , wherein the at least one chain extending agent is present in an amount from 0.10 weight % to 1 weight %, based on the total weight of the polymer composition.

12. The polymer composition according to claim 1 , wherein the weight ratio of chain extending agent to primary antioxidant is from 1:1.1 to 1:3.

13. The polymer composition according to claim 1 , wherein the polymer composition has an inherent viscosity in the range from 0.35 to 1.0 dL/g, as determined in 60/40 (wt/wt) phenol/ tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.

14. The polymer composition according to claim 1 , wherein the at least one phenolic antioxidant is pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, the at least one phosphite is tris(2,4-di-tert-butylphenyl)phosphite, and the at least one chain extending agent is at least one copolymer of glycidyl methacrylate with styrene that has an average of 5 to 20 pendant epoxy groups per molecule.

15. The polymer composition according to claim 1 , wherein the polymer composition comprise: (1) at least one phenolic antioxidant in the amount of from 0.01 weight % to 2.0 weight %, (2) at least one phosphite in the amount of from 0.01 weight % to 2.0 weight %, and (3) at least one chain extending agent in the amount of from 0.01 weight % to 2.0 weight percent, based on the total weight of the polymer composition.

16. The polymer composition according to claim 1 , wherein the condensation polymer is amorphous.

17. The polymer composition according to claim 1 , wherein the condensation polymer is a polyester comprising at least one dicarboxylic acid or an ester thereof and at least one diol, wherein the total of acid residues present is 100 mole % and wherein the total of diol residues present is 100 mole %, wherein the dicarboxylic acid or ester thereof component comprises residues of 1,4-cyclohexanedicarboxylic acid or an ester thereof, and wherein the diol component comprises residues of 1,4-cyclohexanedimethanol and polytetramethylene ether glycol.

18. The polymer composition according to claim 1 , wherein the polymer is selected from at least one polyester comprising:

(a) diacid residues comprising from about 70 to about 100 mole percent of terephthalic acid (TPA) residues and 0 to about 30 mole percent isophthalic acid (IPA) residues; and

(b) diol residues comprising from about 20 to about 100 mole percent of 1,4-cyclohexanedimethanol (CHDM) residues and 0 to 100 mole percent of ethylene glycol;

wherein the total of diacid residues is 100 mole % and wherein the total of diol residues is 100 mole %.

19. The polymer composition according to claim 1 , wherein the polymer is a copolyesterether.

20. The polymer composition according to claim 17 , having an inherent viscosity of from about 0.7 to about 1.5 dL/g, as determined in 60/40 (wt/wt) phenol/ tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C., and comprising:

A. a dicarboxylic acid component consisting essentially of 1,4-cyclohexanedicarboxylic acid,

B. a glycol component consisting essentially of

(1) 1,4-cyclohexanedimethanol, and

(2) from about 15 to about 50 weight percent, or from 20 to 35 weight percent, based on the weight of the polyesterether, of polytetramethyleneether glycol having a weight molecular weight of about 500 to about 2000.