Method for the preparation of a poly(arylene ether), and related compositions

1. A method for preparing a poly(arylene ether), comprising the following steps:

(a) oxidatively coupling a monohydric phenol in the presence of a solvent and a complex metal catalyst, to produce a poly(arylene ether) resin;

(b) removing a portion of the solvent to produce a concentrated solution having a poly(arylene ether) concentration of about 30 to about 60 weight percent and a cloud point T cloud ; and

(c) combining the concentrated solution with an anti-solvent to precipitate the poly(arylene ether) in the form of a precipitation mixture;

wherein the concentrated solution has a temperature of at least about (T cloud −10° C.) immediately before it is combined with the anti-solvent; and

wherein the precipitation mixture has a temperature of at least about T cloud after its formation.

2. The method of claim 1 , wherein the monohydric phenol comprises at least one structural unit of the formula

wherein each Q 1 is independently selected from the group consisting of halogen, C 1 –C 7 primary or secondary alkyl, phenyl, C 1 –C 7 haloalkyl, C 1 –C 7 aminoalkyl, C 1 –C 7 hydrocarbonoxy, and C 2 –C 7 halohydrocarbonoxy, wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q 2 is independently selected from the group consisting of hydrogen, halogen, C 1 –C 7 primary or secondary alkyl, phenyl, C 1 –C 7 haloalkyl, C 1 –C 7 hydrocarbonoxy, and C 2 –C 7 halohydrocarbonoxy, wherein at least two carbon atoms separate the halogen and oxygen atoms.

3. The method of claim 1 , wherein the monohydric phenol comprises 2,6-dimethylphenol and 2,3,6-trimethylphenol.

4. The method of claim 3 , wherein the weight ratio of 2,6-dimethylphenol to 2,3,6-trimethylphenol is in the range of about 1:1 to about 20:1.

5. The method of claim 1 , wherein the anti-solvent has a temperature of at least about (T cloud −45° C.) immediately before being combined with the concentrated solution.

6. The method of claim 1 , wherein the precipitation mixture has a temperature of at least about (T cloud +10° C.) after its formation.

7. The method of claim 1 , wherein the anti-solvent has a temperature of at least about (T cloud −50° C.) immediately before being combined with the concentrated solution.

8. The method of claim 1 , wherein the solvent comprises a C 6 –C 18 aromatic hydrocarbon.

9. The method of claim 8 , wherein the solvent is selected from the group consisting of toluene, xylene, and mixtures which contain at least one of toluene and xylene.

10. The method of claim 8 , wherein the solvent further comprises a C 3 –C 8 aliphatic alcohol.

11. The method of claim 8 , wherein the solvent further comprises methanol, ethanol, or a mixture comprising at least one of methanol and ethanol.

12. The method of claim 1 , wherein the anti-solvent is selected from the group consisting of alcohols having 1 to about 10 carbon atoms; ketones having about 3 to about 10 carbon atoms; alkanes having about 5 to about 10 carbon atoms; and combinations comprising at least one of the foregoing materials.

13. The method of claim 12 , wherein the anti-solvent comprises methanol.

14. The method of claim 1 , wherein the complex metal catalyst comprises at least one metal ion selected from Group VIB, VIIB, VIII or IB of the Periodic Table.

15. The method of claim 14 , wherein the complex metal catalyst comprises copper ions.

16. The method of claim 14 , wherein the complex metal catalyst further comprises at least one nitrogen-containing ligand.

17. The method of claim 16 , wherein the nitrogen-containing ligand is selected from the group consisting of alkylenediamine ligands, primary monoamines, secondary monoamines, tertiary monoamines, aminoalcohols, oxines, and combinations comprising at least one of the foregoing nitrogen-containing ligands.

18. The method of claim 1 , wherein:

(i) the monohydric phenol comprises 2,6-dimethylphenol and 2,3,6-trimethylphenol;

(ii) the solvent is selected from the group consisting of toluene, xylene, and mixtures which contain at least one of toluene and xylene;

(iii) the anti-solvent comprises methanol; and

(iv) the precipitation mixture has a temperature of at least about 44° C. after its formation.

19. The method of claim 18 , wherein the precipitation mixture has a temperature of at least about 48° C. after its formation.

20. The method of claim 19 , wherein the precipitation mixture has a temperature of at least about 51° C. after its formation.

21. The method of claim 18 , wherein the anti-solvent further comprises at least one of toluene and water.

22. The method of claim 18 , wherein the anti-solvent comprises about 70 weight % to about 100 weight % methanol; 0 weight % to about 20 weight % toluene; and 0 weight % to about 10 weight % water.

23. The method of claim 1 , wherein the temperature of the precipitation mixture is controlled in a manner sufficient to reduce the level of particles smaller than about 38 microns in the precipitated poly(arylene ether), to less than about 18% by weight.

24. A method for preparing a poly(arylene ether), comprising the following steps:

(a) oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol in the presence of a complex metal catalyst and a solvent comprising at least one of toluene and xylene, to produce a poly(arylene ether) copolymer resin;

(b) removing a portion of the solvent to produce a concentrated solution having a poly(arylene ether) concentration of about 25 to about 60 weight percent and a cloud point T cloud ; and

(c) combining the concentrated solution with an anti-solvent which comprises at least about 50 weight % methanol, to precipitate the poly(arylene ether) copolymer in the form of a precipitation mixture;

wherein the concentrated solution has a temperature of at least about (T cloud −10° C.) immediately before it is combined with the anti-solvent; and

wherein the precipitation mixture has a temperature of at least about (T cloud +10° C.) after its formation.

25. The method of claim 24 , wherein

the concentrated solution comprises about 25 weight % to about 55 weight % poly(arylene ether);

the complex metal catalyst comprises copper ion, a secondary alkylenediamine ligand, a secondary monoamine, and a tertiary monoamine;

the complex metal catalyst is recovered with an aqueous solution after step (a); and wherein

the precipitated poly(arylene ether) copolymer has an intrinsic viscosity of about 0.25 dL/g to about 0.50 dL/g.

26. A method for preparing a poly(arylene ether), comprising the following steps:

(I) oxidatively coupling 2,6-dimethylphenol and 2,3,6-trimethylphenol in the presence of a complex metal catalyst and a solvent comprising at least one of toluene and xylene, to produce a poly(arylene ether) copolymer resin;

(II) removing a portion of the solvent to produce a concentrated solution having a poly(arylene ether) concentration of about 30 to about 60 weight percent and a cloud point T cloud ; and

(III) combining the concentrated solution with an anti-solvent, to precipitate the poly(arylene ether) copolymer in the form of a precipitation mixture;

wherein the concentrated solution has a temperature T, immediately before it is combined with the anti-solvent; and T satisfies the inequality

T >([ S φ−(0.296 ×IV+ 1.27 ×TMP− 35.711]/[1.97(1×0.00795 ×IV− 0.0249 ×TMP]− 10),

 wherein φ S is the polymer concentration (expressed in weight %), IV is the intrinsic viscosity of the copolymer in chloroform at 25° C. (expressed in mL/g), and TMP is the 2,3,6-trimethylphenol content of the copolymer (expressed in weight %); and

wherein the precipitation mixture has a temperature of at least about T cloud after its formation.

27. A poly(arylene ether) copolymer powder prepared according to the method of claim 1 , comprising 2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenylene ether units, having an intrinsic viscosity of about 0.25 dL/g to about 0.50 dL/g, and containing less than about 18% by weight of particles smaller than about 38 micrometers.

28. The poly(arylene ether) copolymer powder of claim 27 , containing less than about 15% by weight of particles smaller than about 38 micrometers.

29. The poly(arylene ether) copolymer powder of claim 27 , wherein the weight ratio of 2,6-dimethyl-1,4-phenylene ether units to 2,3,6-trimethyl-1,4-phenylene ether units is about 3:1 to about 6:1; and the copolymer has a Tg of at least about 220° C.

30. A poly(arylene ether) prepared by the method of claim 1 , and comprising less than about 18% by weight of particles smaller than about 38 micrometers.

31. A thermoplastic composition comprising the poly(arylene ether) of claim 30 .

32. The thermoplastic composition of claim 31 , further comprising a polyamide resin.

33. The method of claim 1 , wherein the concentrated solution has a temperature of at least about 60° C.

34. The method of claim 1 , wherein the concentrated solution has a temperature of at least about 70° C.

35. The method of claim 1 , wherein the concentrated solution has a temperature of at least about 80° C.

36. The method of claim 1 , wherein the concentrated solution has a temperature of at least about 90° C.