Process for drying polymeric materials

1. Process for drying a moist polymeric material comprising fluorine permanently bonded thereto to obtain a dried polymeric material having a reduced non-permanently bonded fluorine impurity level, comprising the steps of:

(a) mixing the moist polymeric material with an aqueous solution of a carbohydrate to afford a mixture of the moist polymeric material with the carbohydrate;

(b) heating and/or filtering the mixture of the moist polymeric material with the carbohydrate to remove an amount of volatiles to obtain a pre-dried polymeric material having a volatiles content VC pre-dried (pre-drying step);

(c) fluidizing the pre-dried material in a fluidized bed in order to further remove an amount of volatiles to obtain the dried polymeric material having a volatiles content VC dried (fluidized bed drying step), the pre-dried material having a temperature of at most about 50° C. while in the fluidized bed; and

(d) withdrawing and collecting the dried polymeric material from the fluidized bed;

wherein VC pre-dried is higher than VC dried , and the moist polymeric material comprises at least a polymeric material, said polymeric material comprises fluorine permanently bonded to said polymeric material, wherein the VC pre-dried is at most 42% and wherein the dried polymeric material has a reduced non-permanently bonded fluorine level.

2. Process according to claim 1 , wherein the pre-drying step of the process of claim 1 , further comprises blowing or sucking a gas through the moist polymeric material.

3. The process of claim 2 , wherein the gas is an inert gas.

4. The process of claim 3 , wherein the inert gas is nitrogen.

5. Process according to claim 1 or 2 , wherein the moist polymeric material comprises a polymer or copolymer selected from the group consisting of: α,β-unsaturated acid, salts, esters or amide derivatives thereof; a polyamide; a polyesterimide; a polyester; a polyolefine; a polyurethane; a polyamine; a polyepoxy; a polyether; or combinations thereof.

6. Process according to claim 1 or 2 , wherein the moist polymeric material comprises an at least partially crosslinked polymeric material.

7. Process according to claim 6 , wherein the at least partially crosslinked polymeric material comprises:

i) a substituted acrylic acid derivative or an ester, amide or salt thereof, in the amount of 50-96% w/w of said polymeric material; and

ii) one or more alkenes in the amount of 1-50% w/w of said polymeric material; and

iii) divinylbenzene in the amount of 3-7% w/w of said polymeric material.

8. The process of claim 7 , wherein said substituted acrylic acid derivative is calcium 2-fluoroacrylate in an amount of about 85-95% w/w of said polymeric material.

9. The process of claim 7 , wherein said one or more alkenes is octadiene in an amount of about 3-7% w/w of said polymeric material.

10. The process according to claim 7 , wherein said substituted acrylic acid derivative is calcium 2-fluoroacrylate in an amount of about 85 to about 95% w/w of said polymeric material.

11. The process according to claim 7 , wherein said one or more alkenes is octadiene in an amount of about 3 to about 7% w/w of said polymeric material.

12. Process according to claim 1 or 2 , wherein no heating is applied in the pre-drying step.

13. Process according to claim 1 or 2 , wherein the VC dried is at least 10%.

14. The process of claim 13 , wherein VC dried is measured with a halogen moisture analyser, wherein a light metal scale pan is tarred on a integrated analytical balance of the halogen moisture analyser before weighing the mass of a pre-dried polymeric material; afterwards 2 g of a moist polymeric material (M dried ) are scattered over the whole scale pan surface and said sample is heated at 160° C. for 45 min; upon said heating, the M dried upon heating at 160° C. for 45 min in the analytical balance is recorded, and VC dried (%)=100×(M dried −M dried upon heating at 160° C. for 45 min )/M dried ).

15. Process according to claim 1 or 2 , wherein the carbohydrate is a mono- and/or poly-saccharide.

16. The process of claim 15 , wherein the concentration of the aqueous solution of a carbohydrate is at least 5 and at most 60% w/w.

17. The process of claim 15 , wherein the carbohydrate is sorbitol.

18. The process according to claim 15 , wherein the concentration of the aqueous solution of a carbohydrate is at least 5 and at most 60% w/w.

19. The process according to claim 15 , wherein the carbohydrate is sorbitol.

20. The process of claim 1 , wherein VC pre-dried is measured with a halogen moisture analyser, wherein a light metal scale pan is tarred on a integrated analytical balance of the halogen moisture analyser before weighing the mass of a pre-dried polymeric material; afterwards 2 g of a moist polymeric material (M pre-dried ) are scattered over the whole scale pan surface and said sample is heated at 160° C. for 45 min; upon said heating, the M pre-dried upon heating at 160° C. for 45 min in the analytical balance is recorded, and VC pre-dried (%)=100×(M pre-dried −M pre-dried upon heating at 160° C. for 45 min )/M pre-dried ).

21. The process of claim 1 or claim 2 , wherein VC pre-dried is at least 5%, at least 8%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 30% by weight.

22. The process of claim 1 or claim 2 , wherein VC dried is at least 0%, at least 1%, at least 3%, at least 6%, at least 8%, at least 10%, at least 12%, or at least 14% by weight.

23. The process of claim 1 or claim 2 , wherein VC dried is at most 40%, at most 35%, at most 30%, at most 28%, at most 25%, at most 22%, or at most 20% by weight.