Fluoropolymer compositions
View Patent ↗A composition for solubilizing a fluoropolymer is described. Further described, is how the fluoropolymer composition is obtained, as well as the process for its preparation and its use as a coating applicant. The composition can include a solubilized fluoropolymer and a solvent blend of a diester and dimethylsulfoxyde.
1. A fluoropolymer composition comprising:
a solvent blend comprising:
a diester of formula (I):
R 1 —OOC-A-COO—R 2 (I),
wherein R 1 and R 2 , identical or different, are C 1 -C 20 alkyl, aryl, alkylaryl, or arylalkyl groups, linear or branched, cyclic or non cyclic, and
A is a linear or branched divalent alkylene group, and
dimethylsulfoxide (DMSO); and
a fluoropolymer solubilized in the solvent blend.
2. The composition as defined by claim 1 , wherein R 1 and R 2 , identical or different are selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-hexyl, isooctyl, 2-ethylhexyl, cyclohexyl, phenyl and benzyl.
3. The composition as defined by claim 1 , wherein the diester is a mixture of different diesters of formula (I).
4. The composition as defined by claim 1 , wherein A is C 3 -C 10 branched divalent alkylene.
5. The composition as defined by claim 1 , wherein A is selected from the group consisting of the following:
A MG of formula —CH(CH 3 )—CH 2 —CH 2 —,
A ES of formula —CH(C 2 H 5 )—CH 2 —, and their mixtures.
6. The composition as defined by claim 1 , wherein the diester has the following formula:
CH 3 —OOC—CH(CH 3 )—CH 2 —CH 2 —COO—CH 3 .
7. The composition as defined by claim 1 , wherein the diester is a mixture comprising diesters of the following formula (I′), (I″) and optionally (II):
R 1 —OOC-A MG -COO—R 2 (I′)
R 1 —OOC-A ES -COO—R 2 (I″), and
optionally R 1 —OOC—(CH 2 ) 4 —COO—R 2 (II),
wherein:
A MG is —CH(CH 3 )—CH 2 —CH 2 —,
A ES is —CH(C 2 H 5 )—CH 2 —.
8. The composition as defined by claim 7 , wherein R 1 and R 2 are methyl groups.
9. The composition as defined by claim 7 , wherein the mixture of diesters comprises:
from 70% to 95% by weight of diester of formula (I′),
from 5% to 30% by weight of diester of formula (I″), and
from 0% to 10% by weight of diester of formula (II).
10. The composition as defined by claim 1 , wherein A is a divalent alkylene group of formula (CH 2 ) r , wherein r is an average number of from 2 to 4.
11. The composition as defined by claim 10 , wherein the diester is a mixture of dimethyladipate (r=4), dimethylglutarate (r=3) and diméthylsuccinate (r=2), or a mixture of diethyladipate (r=4), diethylglutarate (r=3) and diethylsuccinate (r=2), or a mixture of diisobutyladipate (r=4), diisobutylglutarate (r=3) and diisobutylsuccinate (r=2).
12. The composition as defined by claim 11 , wherein the diester is a mixture comprising:
from 9% to 17% by weight of dimethyladipate,
from 59% to 67% by weight of dimethylglutarate, and
from 20% to 28% by weight of dimethylsuccinate.
13. The composition as defined by claim 1 , wherein the weight ratio between the diester and DMSO is of from 1/99 to 99/1.
14. The composition as defined by claim 13 , wherein the weight ratio between the diester and DMSO is from 20/80 to 80/20.
15. The composition as defined by claim 13 , wherein the weight ratio between the diester and DMSO is from 70/30 to 30/70.
16. The composition as defined by claim 1 , wherein the diester is dimethylsuccinate.
17. The composition as defined by claim 1 , wherein the fluoropolymer is polyvinylidene_fluoride (PDVF) and copolymer of vinylidene fluoride with comonomers hexafluoropropylene (HFP) and/or chlorotrifluoroethylene (CTFE).
18. The composition as defined by claim 1 , wherein the amount of fluoropolymer is of from 1% to 15% by weight.
19. The composition as defined by claim 1 , wherein the composition comprises an odor masking agent.
20. The composition as defined by claim 1 , wherein the composition comprises an anti freezing agent.
21. A process of preparing the composition as defined by claim 1 , wherein the process comprises the steps of:
preparing the solvent blend by mixing a diester of formula (I) and dimethylsulfoxide,
introducing the solvent blend into the fluoropolymer, under stirring, and
heating the mixture at a temperature form room temperature to a temperature equal to or below 100° C., thereby solubilizing the fluoropolymer and forming the fluoropolymer composition of claim 1 .
22. The process as defined by claim 21 , further comprising cooling down the mixture.
23. The process as defined by claim 21 , wherein the solvent blend is heated at a temperature from 30° C. to 80° C.
24. A process of preparing the composition as defined by claim 1 , wherein the process of preparation comprises the steps of:
preparing the solvent blend by mixing a diester of formula (I) and dimethylsulfoxide,
heating the solvent blend at a temperature from room temperature to a temperature equal to or below 100° C., and
introducing the fluoropolymer into the solvent blend, thereby solubilizing the fluoropolymer and forming the fluoropolymer composition of claim 1 .
25. The process as defined by claim 24 , wherein the solvents blend is heated to a temperature from 30° C. to 80° C.
26. A method of preparing a membrane, a foam or a substrate coating, the method comprising preparing the membrane foam or coating using the fluoropolymer composition as defined by claim 1 as a raw material for the membrane, foam or coating.
27. A process for coating a substrate, the process comprising applying the fluoropolymer composition as defined by claim 1 onto one or two sides of the substrate or parts thereof and removing the solvent.
28. The process as defined by claim 27 , wherein the substrate is a battery separator material.
29. A method of recycling fluoropolymer, the method comprising using the solvent blend as defined by claim 1 in the recovery of PVDF from a backing of a photovoltaic panel or a wire coating, thereby forming the fluoropolymer composition of claim 1 .