LOCAs cure rapidly with UV, moisture

Additions to Henkel’s Loctite line of liquid, optically clear adhesives (LOCAs), 5191 and 5193 silicone adhesives feature a patented chemical breakthrough that increases cure speed and improves optical properties. Specifically designed for direct bonding of cover lenses or touch panel sensors to LCDs, the adhesives are fully compatible with either 365-nm (UV) or 405-nm (violet) LED light sources.

5191, which can be used with its matching 5191DM dam, cures on exposure to UV light and is easier to handle in some lamination equipment, while 5193 cures not only on exposure to UV, but also with moisture, which is particularly helpful in shadowed areas. The low viscosity LOCAs are designed for high efficiency production processes, requiring only 2,000 mJ of energy for full cure in less than 2 s (3 to 10 times less energy than traditional one-part silicone LOCAs), and a 750-µm thick lamination delivers a b* value of 0.3 for yellowing and 0.2% haze after 500 hrs QUV aging (50% less yellowing and 95% less haze compared to traditional one-part silicone LOCAs).