The following ether compounds and their use. In the formula (1), n represents 0 or 1, m represents an integer of 0 to 2, Y represents —O—, —S—, —C (═O) —O— and —O. —C (═O) —, wherein X 1 and X 2 represent a hydrogen atom or a fluorine atom, and R represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms substituted with one or more fluorine atoms. However, when m is 0, the carbon number of R is 3-20. R may intervene an oxygen atom, a sulfur atom and a carbonyl group in the middle of bonding.
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