As a membrane switch panel, it is mainly responsible for product appearance of decoration and protection, so used to make panel film, should at least have the following conditions:
(1) the good appearance: refers to the production of the panel surface level off, luster, no mechanical damage, scratches, surface defects such as inclusions and splash.
(2) good weather resistance: panel layer is surface layer of the membrane switch exposure in the natural environment, its panel material to be under the certain condition of the natural environment, not out of shape, craze, aging and change color, etc.
(3) good chemical resistance: panel layer is likely to be hit different chemicals, but for most of common chemicals, such as alcohol, ether, mineral oil should have certain tolerance ability.
Panel (4) good dimensional stability: requirements of thin film, in a certain temperature range (general - 40 ℃ ~ 55 ℃) size size has no obvious change.
(5) elastic demands: panel thin layer has a certain weak performance, at the same time, the elastic deformation and elongation of the material can be use to judge, in general elongation, elastic deformation is big also, add the difference on elastic energy.
According to the above requirements, used in the film usually have poly acid ester of panel, PVC, polyester and polyurethane etc. Several kinds of thin film.