Membrane switch is composed of multilayer film adhesive as a whole, so it need to have several thin film layers of adhesive. The membrane switch manufacturing process with double sided adhesive for the application of the media has a downward trend, the interlining part has been gradually replaced by "sandwich" prefabricated interlayer, the panel and the bottom layer of adhesive, adopt the method of screen printing emulsion for rubber is on the development trend. Screen printing equal viscosity latex with double-sided adhesive, but the cost is low, bonding process won't produce bubbles, surface is flat and level. Especially in the application of panel layer, can be controlled by printing emulsion area graphics, avoid the window, hole site need to get rid of the trouble respectively. Screen printing emulsion process should pay attention to the following aspects:
1. The coarse mesh. Only the coarser mesh, conducive to the smooth paste emulsion through, general appropriate chooses 60 a 80 mesh coarse mesh.
2. Water resistance. Due to screen printing latex is a water-soluble gel, emulsion containing a large number of moisture, if the usual oil resistance photosensitive film, graphics easy damaged, water resistance photosensitive plastic plate should be adopted. If every sensitive glue water resistance, should be made on the screen, using water resistant coating protection graphics, because of its method is more, from here.
3. Thick film layer. Thicker coating membrane layer, especially in the network version of the printing film layer is much thicker than the scraping the mask layer is, the general should guarantee the wet thickness was printed in 80 ~ 80 microns.
4. The orange peel. Screen printing rubber plate making graphics, cannot use field version of the flat shape seal layer, and should adopt irregular orange peel shape screen graphics, only a few independent of the composition of the orange peel patterns is possible using the independent boundary, under surface tension was printed, allow the graphics accumulation is thicker and not diaspora, orange peel shape graphics in the paste at the same time can release the adhesive layer in the air, after the paste can adjust viscose contact surface, make the space of colloid have stretch, achieve the purpose of smooth paste.