Ethylene/tetrafluoroethylene copolymer
View Patent ↗To provide an ethylene/tetrafluoroethylene copolymer which is excellent in heat resistance and flexibility. An ethylene/tetrafluoroethylene copolymer comprising repeating units (A) based on tetrafluoroethylene and repeating units (B) based on ethylene in a ratio of repeating units (A)/repeating units (B)=66/34 to 75/25 (molar ratio) and as an optional component, repeating units (C) based on a monomer represented by CH 2 ═CX(CF 2 ) n Y (wherein each of X and Y which are independent of each other is a hydrogen atom or a fluorine atom, and n is from 2 to 8) in an amount of from 0 to 1 mol % based on the total number of moles of the repeating units (A) based on tetrafluoroethylene and the repeating units (B) based on ethylene, and having a volume flow rate measured at 297° C. of from 4 to 1,000 mm 3 /sec and an elastic modulus of at most 500 MPa.
1. An ethylene/tetrafluoroethylene copolymer consisting of repeating units
(A) based on tetrafluoroethylene,
(B) based on ethylene in a ratio of repeating units (A)/repeating units (B)=70.9/29.1 to 75/25 (molar ratio), and as an optional component, repeating units
(C) based on a monomer represented by CH 2 ═CX(CF 2 ) n Y wherein each of X and Y which are independent of each other is a hydrogen atom or a fluorine atom, and n is from 2 to 8 in an amount of from 0 to 1 mol % based on the total number of moles of the repeating units (A) and (B),
said ethylene/tetrafluoroethylene copolymer having a volume flow rate measured at 297° C. of from 4 to 1,000 mm 3 /sec and an elastic modulus of at most 500 MPa.
2. The ethylene/tetrafluoroethylene copolymer according to claim 1 , wherein the ethylene/tetrafluoroethylene copolymer further consists of the repeating units (C).
3. The ethylene/tetrafluoroethylene copolymer according to claim 2 , wherein the monomer represented by CH 2 ═CX(CF 2 ) n Y is CH 2 ═CH(CF 2 ) 2 F or CH 2 ═CH(CF 2 ) 4 F.
4. The ethylene/tetrafluoroethylene copolymer according to claim 3 , wherein the monomer represented by CH 2 ═CX(CF 2 ) n Y is CH 2 ═CH(CF 2 ) 4 F.
5. The ethylene/tetrafluoroethylene copolymer according to claim 2 , consisting of repeating units
(A) based on tetrafluoroethylene,
(B) based on ethylene in a ratio of repeating units (A)/repeating units (B)=70.9/29.1 to 75/25 (molar ratio), and
(C) based on a monomer represented by CH 2 ═CX(CF 2 ) n Y wherein each of X and Y which are independent of each other is a hydrogen atom or a fluorine atom, and n is from 2 to 8 in an amount of from 0.1 to 1 mol % based on the total number of moles of the repeating units (A).
6. The ethylene/tetrafluoroethylene copolymer according to claim 5 , wherein the monomer represented by CH 2 ═CX(CF 2 ) n Y is CH 2 ═CH(CF 2 ) 4 F.
7. The ethylene/tetrafluoroethylene copolymer according to claim 2 , wherein the ethylene/tetrafluoroethylene copolymer has a melting point of at least 230° C.
8. The ethylene/tetrafluoroethylene copolymer according to claim 2 , wherein the ethylene/tetrafluoroethylene copolymer has a melting point of at least 235° C.
9. The ethylene/tetrafluoroethylene copolymer according to claim 8 , wherein said ethylene/tetrafluoroethylene copolymer has a volume flow rate measured at 297° C. of from 4 to 100 mm 3 /sec.
10. A method for producing the ethylene/tetrafluoroethylene copolymer as defined in claim 1 , which comprises copolymerizing ethylene, tetrafluoroethylene and as an optional component, a monomer represented by CH 2 ═CX(CF 2 ) n Y wherein each of X and Y which are independent of each other is a hydrogen atom or a fluorine atom, and n is from 2 to 8 in the presence of a radical polymerization initiator, a chain transfer agent and a polymerization medium.
11. The ethylene/tetrafluoroethylene copolymer according to claim 1 , wherein the ethylene/tetrafluoroethylene copolymer does not contain repeating units (C).
12. The ethylene/tetrafluoroethylene copolymer according to claim 11 , consisting of repeating units
(A) based on tetrafluoroethylene, and
(B) based on ethylene in a ratio of repeating units (A)/repeating units (B)=70.9/29.1 to 75/25 (molar ratio).
13. The ethylene/tetrafluoroethylene copolymer according to claim 11 , wherein the ethylene/tetrafluoroethylene copolymer has a melting point of at least 230° C.
14. The ethylene/tetrafluoroethylene copolymer according to claim 11 , wherein the ethylene/tetrafluoroethylene copolymer has a melting point of at least 235° C.
15. The ethylene/tetrafluoroethylene copolymer according to claim 14 , said ethylene/tetrafluoroethylene copolymer has a volume flow rate measured at 297° C. of from 4 to 100 mm 3 /sec.
16. The ethylene/tetrafluoroethylene copolymer according to claim 1 , wherein said elastic modulus is from 400 to 500 MPa.