Method of making relaxor ferroelectric fluoropolymers
View Patent ↗This disclosure relates to a method of making a fluoropolymer object. The method may include providing a substrate including fluoropolymer comprising units derived from monomers M 1 , M 2 and M 3 , wherein: M 1 is a vinylidene fluoride; M 2 is a monomer of formula (I): CX 1 X 2 ═CX 3 X 4 , wherein each of X 1 , X 2 , X 3 and X 4 is independently selected from H, Cl and F, and wherein at least one of X 1 , X 2 , X 3 and X 4 is F; M 3 is a monomer of formula (II): CY 1 Y 2 ═CY 3 CF 3 , wherein each of Y 1 , Y 2 and Y 3 is independently selected from H, Cl, F, Br, I and alkyl groups comprising from 1 to 3 carbon atoms which are optionally partly or fully halogenated; and stretching the substrate.
1. A method of making a fluoropolymer object, comprising:
providing a substrate comprising fluoropolymer comprising units derived from monomers M 1 , M 2 and M 3 , wherein:
M 1 is a vinylidene fluoride;
M 2 is a monomer of formula (I): CX 1 X 2 ═CX 3 X 4 , wherein each of X 1 , X 2 , X 3 and X 4 is independently selected from H, Cl and F, and wherein at least one of X 1 , X 2 , X 3 and X 4 is F;
M 3 is a monomer of formula (II): CY 1 Y 2 ═CY 3 CF 3 , wherein each of Y 1 , Y 2 and Y 3 is independently selected from H, Cl, F, Br, I and alkyl groups comprising from 1 to 3 carbon atoms;
stretching the substrate at a temperature higher than the Curie transition temperature of the fluoropolymer of the substrate; and
wherein no thermal annealing is performed after stretching the substrate at a temperature higher than the Curie transition temperature of the fluoropolymer of the substrate.
2. The method of claim 1 , wherein the fluoropolymer object is a fluoropolymer film or a fluoropolymer fiber.
3. The method of claim 1 , wherein the substrate is stretched at a temperature from 20 to 120° C.
4. The method of claim 3 , wherein the substrate is stretched at a temperature from 60 to 120° C.
5. The method of claim 1 , wherein the substrate is stretched by at least 150%.
6. The method of claim 1 , wherein the substrate is stretched in one direction.
7. The method of claim 6 , wherein the substrate is stretched in two directions.
8. The method of claim 1 , wherein M 2 is selected from the group of trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene and 1,1-chlorofluoroethylene.
9. The method of claim 1 , wherein each of Y 1 , Y 2 and Y 3 is independently selected from H, Cl, F, Br and I.
10. The method of claim 1 , wherein M 3 is selected from the group of hexafluoropropene, 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1-chloro-3,3,3-trifluoropropene and 2-chloro-3,3,3-trifluoropropene.
11. The method of claim 1 , wherein the proportion of units derived from the M 1 monomers in the fluoropolymer is from 15 to 55 mol. %, relative to the total of units derived from the M 1 and M 2 monomers.
12. The method of claim 1 , wherein the fluoropolymer comprises less than 15 mol. % of units derived from the M 3 monomers.
13. The method of claim 1 , wherein providing the substrate comprises shaping the fluoropolymer into the substrate.
14. The method of claim 13 , wherein shaping the fluoropolymer into the substrate comprises extruding or hot pressing the fluoropolymer into the substrate.
15. The method of claim 1 , wherein providing the substrate comprises manufacturing the fluoropolymer by polymerizing monomers M 1 , M 2 and M 3 .
16. The method of claim 1 , wherein the alkyl groups comprising from 1 to 3 carbon atoms are partially halogenated.