| Résumé : |
The author explains the advantages of the latest polyester coatings for the production of keyboards, touch screens and electronic display windows.
Polyester, or PET (Polyethylene Terephthalate) is today commonly used in a wide range of electronics and interface applications: membrane touch panels; display windows and touch screens. In its raw form, however, polyester has limitations which only specialist coating technology can overcome. Prior to the introduction of specialist coated polyester films, polycarbonate had generally been selected for these applications. However, in applications where the film substrate is mechanically stressed, such as embossed (tactile) membrane touch switches, or where there is exposure to all but the most benign of solvents and chemicals, polycarbonate is an unsuitable choice. Typically, in polycarbonate tactile membrane switches, operating life is measured in the thousands rather than millions of operations. In terms of chemical resistance, polycarbonate is susceptible to attack by ketones, ethers and aromatic and chlorinated hydrocarbons. This means that even common products like petrol, brake fluid, most lubricating oils, paints and varnishes can badly affect the surface of polycarbonate switch panels. The relatively poor mechanical and chemical characteristics of polycarbonate are due largely to its amorphous (or formless) chemical structure. This means that the polymer molecules are relatively weakly linked together. |
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Stretching polyester limits in POLYMERS PAINT COLOUR JOURNAL - PPCJ, Vol. 195, N° 4488 (05/2005)
