| abstract |
Membrane switch film having excellent handling properties and durability composed mainly of polyethylene-2,6-naphthalenedicarboxylate, particularly suitable for membrane switches used in automobiles in automobiles that may be exposed to high temperatures. A film is provided.n n n In this film, the refractive index of both surfaces is in the range of 1.770-1.790 in at least one direction of a film production direction and the width direction, and the difference of the refractive index of both surfaces is 0.015 or less in absolute value,n n n The melting sub peak temperature of the film measured by differential scanning calorimeter (DSC) is 220 degreeC or more and 250 degrees C or less, and the difference of the melting sub peak temperature on one surface and the melting sub peak temperature on the other surface is an absolute value. It consists of the film for membrane switches which are 6 degrees C or less. |