Tube, method for producing tube, and method for storing tube
Provided is a tube comprising a tetrafluoroethylene/fluoroalkyl vinyl ether copolymer, wherein the tube inner surface has a surface roughness Ra of 5 nm or less measured by atomic force microscopy (AFM) with an evaluation length set to 3 μm, and the tube has an amount of metals eluted from the tube inner surface of 0.30 ng/cm 2 or less.
1 . A tube comprising a tetrafluoroethylene/fluoroalkyl vinyl ether copolymer,
wherein the tube inner surface has a surface roughness Ra of 5 nm or less measured by atomic force microscopy (AFM) with an evaluation length set to 3 μm, and
the tube has an amount of metals eluted from the tube inner surface of 0.30 ng/cm 2 or less.
2 . The tube according to claim 1 , wherein the tube inner surface has an average spherulite size of 1 to 150 μm.
3 . The tube according to claim 1 , wherein the tube inner surface has an average spherulite size of more than 15 μm.
4 . The tube according to claim 1 , wherein the fluoroalkyl vinyl ether is perfluoro(propyl vinyl ether).
5 . The tube according to claim 1 , wherein the tube is used for transporting a high-purity chemical solution for manufacturing a semiconductor device.
6 . The tube according to claim 1 , wherein the tube is obtained by extruding the tetrafluoroethylene/fluoroalkyl vinyl ether copolymer, while flowing a gas which has passed through a filter having a filtration accuracy of 5 nm or less into a hollow part of a tube extruded from the die equipped in an extruder.
7 . The tube according to claim 1 , wherein the content of a fluoroalkyl vinyl ether unit in the tetrafluoroethylene/fluoroalkyl vinyl ether copolymer is 1.0 to 8.0 mass % relative to the total monomer units.
8 . A method for producing the tube according to claim 1 , comprising, by using an extruder in which a die is equipped, extruding the tetrafluoroethylene/fluoroalkyl vinyl ether copolymer, while flowing a gas which has passed through a filter having a filtration accuracy of 5 nm or less into a hollow part of a tube extruded from the tip of the die.
9 . The production method according to claim 8 , wherein a resin temperature of the tetrafluoroethylene/fluoroalkyl vinyl ether copolymer at the tip of the die is 350 to 370° C.
10 . A method for storing the tube according to claim 1 , comprising storing the tube with a high-purity liquid filled inside the tube.