Ethylene-tetrafluoroethylene copolymer sheet and method for producing same
View Patent ↗An ethylene/tetrafluoroethylene copolymer sheet obtained by extrusion, has R 0 /d, wherein R 0 is an in-plane phase difference [unit: nm]and d is a thickness, [unit: nm], of at most 3.0×10 −3 , and a thickness of more than 300 μm. The ethylene/tetrafluoroethylene copolymer sheet preferably has a thickness of from 305 to 3,000 μm . A process for producing an ethylene/tetrafluoroethylene copolymer sheet includes melting an ethylene/tetrafluoroethylene copolymer to obtain a melt, continuously extruding the melt through a die for shaping the melt to a sheet, and letting the sheet pass between two rolls. One of the two rolls is a rigid roll, and the other is an elastic roll. The two rolls are pressed under a linear pressure of from 0.1 to 1,000 N/cm.
1. An ethylene/tetrafluoroethylene copolymer sheet, having R 0 /d, wherein R 0 is an in-plane phase difference [unit: nm]and d is a thickness [unit: nm], of at most 1.0×10 −3 , and a thickness of more than 300μm, wherein the ethylene/tetrafluoroethylene copolymer sheet is an extruded sheet.
2. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the ethylene/tetrafluoroethylene copolymer sheet has a thickness of from 305 to 3,000 μm.
3. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the total luminous transmittance of the ethylene/tetrafluoroethylene copolymer sheet satisfies formula (2):
100≥total luminous transmittance (%)>(−0.022)×(thickness of ethylene/tetrafluoroethylene copolymer sheet) (μm)+96 formula (2).
4. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the acoustic transmission loss with respect to a 500 Hz sound source of the ethylene/tetrafluoroethylene copolymer sheet satisfies formula (3):
acoustic transmission loss (dB)>0 .0085×(thickness of ethylene/tetrafluoroethylene copolymer sheet) (μm)+1.58 Formula (3).
5. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the tensile stress at yield at 23° C. of the ethylene/tetrafluoroethylene copolymer sheet satisfies formula (4):
tensile stress at yield (N/cm)>0.015×(thickness of ethylene/tetrafluoroethylene copolymer sheet) (μm) Formula (4).
6. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the ethylene/tetrafluoroethylene copolymer sheet is a membrane material for a membrane structure building.
7. The ethylene/tetrafluoroethylene copolymer sheet according to claim 1 , wherein the ethylene/tetrafluoroethylene copolymer sheet has a thickness of from 400 to 1,500 μm.
8. A process for producing the ethylene/tetrafluoroethylene copolymer sheet as defined in claim 1 , the process comprising:
melting an ethylene/tetrafluoroethylene copolymer to obtain a melt;
continuously extruding the melt through a die for shaping the melt to a sheet;
letting the sheet pass between two rolls; and
cooling the sheet,
wherein one of the two rolls is a rigid roll, and the other is an elastic roll,
wherein the two rolls are pressed under a linear pressure of from 0.1 to 1,000 N/cm,
wherein the temperature of the melt immediately before passage between the two rolls is from 200 to 330° C., and
wherein the average of the surface temperatures of the two rolls is from 50 to 180° C.
9. A process for producing an ethylene/tetrafluoroethylene copolymer sheet, the process comprising:
melting an ethylene/tetrafluoroethylene copolymer to obtain a melt;
continuously extruding the melt through a die for shaping the melt to a sheet;
letting the sheet pass between two rolls; and
cooling the sheet,
wherein one of the two rolls is a rigid roll, and the other is an elastic roll,
wherein the two rolls are pressed under a linear pressure of from 0.1 to 1,000 N/cm,
wherein the temperature of the melt immediately before passage between the two rolls is from 200 to 330° C., and
wherein the average of the surface temperatures of the two rolls is from 50 to 180° C.