The Preparation And Properties Of One Liquid Optically Clear Adhesive For Capacitive Touch Panels

Capacitive touch panel is coated on the glass layer of transparent conductive thin film, thenthe outer conductive layer plus a protective glass, double glass design can completely protectthe conductive layer and the sensor, capacitive touch panel production mainly uses OCAprocess. But capacitive touch panel can not be repaired, because the adhesive of OCA isstrong. In order to fit the screen size by cropping the OCA. In the production process, OCAmay cause the bubbles or uneven pits, when the baking time.The thesis focus on investigate the liquid optically clear adhesive（LOCA） used in thetouch panel, such the LOCA dispensing on the touch panel is re-workable after UV curing,and the difficulty in rework issue of the defective products of the traditional optically clearadhesive (OCA) assemble with the touch panel can be solved effectively. In addition, theLOCA can dispense and laminate with the cover glass directly and it is different from thetraditional OCA due to the structure of the pressure-sensitive adhesive will degum easilyduring the die-cut process because the adhesive structure isn’t strong enough.In terms of experiment is investigated the different components of UV curing, chemicalstructure, thermal properties, optical properties, UV yellow, peel adhesion and solventresistance for LOCA. The experimental results indicated that the formula which composedas the monofunctional acrylic monomer with the difunctional acrylate modified by butadiene.In terms of optical properties, a refractive index of1.51for the glue, the glass close to thelight transmittance was90%, effectively reducing the light loss; In terms of heat resistance,detected by DSC and DTG, adhesive can withstand the temperature150℃after curing，When the temperature reaches200℃, hot weight loss of the glue is2%; In terms of solventresistance, swelling in different solvents have different effects, the rate of change of weightafter immersion in toluene solvent up to500%When used in the laminating of the touch panel, the adhesive is re-workable even after UVcuring; furthermore, since the adhesive remains in a liquid state so the bonding action can becompleted without any cutting process and decrease the wastage of touch panel.