Poly(aryletherketone)s and process for making them

1. A process for the manufacture of a poly(aryletherketone) (P) comprising:

a. forming a reaction medium by adding to a reactor:

i. at least one α,ω difluorinated monomer (M1) and at least one α,ω dihydroxylated monomer (M2), and/or

ii. at least one a monofluorinated, ω monohydroxylated monomer (M3); then

b. adding to the reactor at least one salt (S1) of an alkali metal (A) other than lithium; then

c. making the monomers and the salt (S1) react together, until the obtention of:

a poly(aryletherketone) (P*) comprising recurring units derived from the monomers and having an intrinsic viscosity η int * superior to 0.7, as measured in methane sulfonic at 30° C. according to ASTM D2857, and

as a by-product, a fluoride salt (S2) of the alkali metal (A),

said salt (S2) having a solubility of more than 5·10 7 mol/kg in acetone at 25° C.,

wherein, at the completion of c, the ratio

[ n M1 +( n M3 /2)]/[ n M2 +( n M3 /2)]

is from 0.97 to 1.03,

where n M1 , n M2 and n M3 are respectively the total number of moles of (M1), (M2) and (M3) which have been added to the reactor until the completion of c; then

d. forming the poly(aryletherketone) (P) from the poly(aryletherketone) (P*), said poly(aryletherketone) (P) having an intrinsic viscosity η int comprised between 0.8·η int * and 1.2·η int *, by adding successively to the reactor:

1. at least one α,ω difluorinated compound (M1′), different from or identical to (M1); then

2. at least one salt (S3) able to react with the fluoride salt (S2) to form a fluoride salt (S4), said salt (S3) having a solubility of more than 5·10 −7 mol/kg in acetone at 25° C. and said fluoride salt (S4) having a solubility of at most 5·10 −7 mol/kg in acetone at 25° C.; then

3. at least one α,ω difluorinated compound (M1″), different from or identical to (M1) and (M1′);

wherein, at the beginning of the addition of the salt (S 3 ), the ratio

[ n M1 +n M1′ +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 1.03,

where n M1′ is the total number of moles of (M1′) which has been added to the reactor after the completion of c and until the beginning of the addition of the salt (S3) and

wherein, at the completion of d, the ratio

[ n M1 +n M1′ +n M1″ +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 1.08,

where n M1″ is the total number of moles of (M1″) which has been added to the reactor after the beginning of the addition of the salt (S3) and until the completion of d; then

e. recovering the poly(aryletherketone) (P) from the reaction medium.

2. The process according to claim 1 , wherein the α,ω difluorinated monomer (M1) is at least one selected from the group consisting of 4,4′-difluorobenzophenone, 1,4-bis(4′-fluorobenzoyl)benzene, and 1,3-bis(4′-fluorobenzoyl)benzene, and wherein the α,ω dihydroxylated monomer (M2) is at least one selected from the group consisting of hydroquinone, 4,4′-dihydroxybenzophenone, 4′4-biphenol, 4,4′-oxybis(phenol), 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 1,6-dihydronaphthalene.

3. The process according to claim 1 , wherein, during c, the monomers and the salt (S1) are reacted together in the presence of a solvent.

4. The process according to claim 1 , wherein the α,ω difluorinated compounds (M1′) and (M1″) are selected, independently from each other, from the group consisting of at least one of 4,4′-difluorobenzophenone and 1,4-bis(4′-fluorobenzoyl)benzene.

5. The process according to claim 1 , wherein the alkali metal (A) is selected from the group consisting of sodium, potassium and mixtures thereof.

6. The process according to claim 5 , wherein the salt (S1) is a mixture of sodium carbonate and potassium carbonate and the fluoride salt (S2) is a mixture of sodium fluoride and potassium fluoride.

7. The process according to claim 1 , wherein the salt (S3) is lithium chloride, and the fluoride salt (S4) is lithium fluoride.

8. The process according to claim 1 , further comprising:

prior to a, b or c, evacuating at least once the reactor under vacuum, and filling at least once the reactor with an inert gas, then;

putting the reactor under a constant purge of the inert gas until the end of d.

9. The process according to claim 1 , wherein the salt (S1) is in the form of a powder and purged with an inert gas, before it is added to the reactor.

10. A poly(aryletherketone) comprising end groups, wherein

more than 40% of the end groups are fluoride end groups, based on the total number of the end groups of the poly(aryletherketone); and the poly-(aryletherketone) meets at least one of the following conditions:

Condition 1: the poly(aryletherketone) comprises fluoride end groups, and complies with the relation:

[ F]·V M 0.29 >265

wherein:

[F] is the content of the fluoride end groups, expressed in μeq/g, and

V M is the melt viscosity of the poly(aryletherketone) at 410° C. and 46.4 s −1 , as measured according to ASTM D3835, expressed in (Pa·s);

Condition 2: less than 70 μeq/g of the end groups are end groups other than fluoride end groups;

Condition 3: the poly(aryletherketone) is in the form of a powder and has a lightness L* of above 86, a* and b* coordinates of respectively between −1 and 1, and between 4 and 16, as measured according to ASTM E308 using Cool White Fluorescent as illuminant; and

Condition 4: the poly(aryletherketone) has a melt viscosity ratio VR 40 , defined as

VR 40 =V 40 /V 10 ,

of between 0.90 and 1.10, wherein V 10 and V 40 represent the melt viscosity at 400° C. and 10 rad/s respectively after 10 and 40 minutes, as measured according to ASTM D4440.

11. The process according to claim 1 , wherein the poly(aryletherketone) (P) comprises end groups and meets at least one of the following conditions:

Condition 1: more than 40% of the end groups are fluoride end groups, based on the total number of the end groups of the poly(aryletherketone);

Condition 2: the poly(aryletherketone) comprises fluoride end groups, and complies with the relation:

[ F]·V M 0.29 >265

wherein:

[F] is the content of the fluoride end groups, expressed in μeq/g, and

V M is the melt viscosity of the poly(aryletherketone) at 410° C. and 46.4 s −1 , as measured according to ASTM D3835, expressed in (Pa·s);

Condition 3: less than 70 μeq/g of the end groups are end groups other than fluoride end groups;

Condition 4: .the poly(aryletherketone) is in the form of a powder and has a lightness L* of above 86, a* and b* coordinates of respectively between −1 and 1, and between 4 and 16, as measured according to ASTM E308 using Cool White Fluorescent as illuminant; and

Condition 5: the poly(aryletherketone) has a melt viscosity ratio VR 40 , defined as

VR 40 =V 40 /V 10 ,

of between 0.90 and 1.10, wherein V 10 and V 40 represent the melt viscosity at 400° C. and 10 rad/s respectively after 10 and 40 minutes, as measured according to ASTM D4440.

12. The process according to claim 1 , wherein the poly(aryletherketone) (P) comprises end groups, more than 40% of said end groups being fluoride end groups, based on the total number of the end groups of the poly(aryletherketone) (P).

13. The process according to claim 1 , wherein the poly(aryletherketone) (P) is a poly(etheretherketone) homopolymer, of which essentially all the recurring units are of formula (VII)

14. The process according to claim 1 , wherein the poly(aryletherketone) (P*) has an intrinsic viscosity η int *, as measured in methane sulfonic at 30° C. according to ASTM D2857, above 0.75 and below 1.5.

15. The process according to claim 1 , wherein the poly(aryletherketone) (P*) has an intrinsic viscosity η int *, as measured in methane sulfonic at 30° C. according to ASTM D2857, above 0.8 and below 1.4.

16. The process according to claim 1 , wherein, at the completion of c, the ratio

[ n M1 +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 0.999 and below 1.02.

17. The process according to claim 1 , wherein, at the beginning of the addition of the salt (S3), the ratio

[ n M1 +n M1′ +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 1.04 and below 1.25.

18. The process according to claim 1 , wherein, at the beginning of the addition of the salt (S3), the ratio

[ n M1 +n M1′ +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 1.05 and below 1.20.

19. The process according to claim 1 , wherein, at the completion of d, the ratio

[ n M1 +n M1′ +n M1″ +( n M3 /2)]/[ n M2 +( n M3 /2)]

is above 1.10 and below 1.20.

20. The process according to claim 1 , wherein the poly(aryletherketone) (P) which is formed from the poly(aryletherketone) (P*) in accordance with d, has an intrinsic viscosity η int above 0.95·η int * and below 1.05·η int *.