Adhesives Magazine

HENKEL CORP.: Silicone Optically Clear Adhesives

July 5, 2013

This company has expanded its line of silicone Loctite®liquid optically clear adhesives (LOCAs) to include patented formulations that reportedly fixture in less than 2 seconds, require 3-10 times less energy to cure than traditional one-part silicone LOCAs, and are compatible with either 365 or 405 nm LED light sources. Specifically designed for direct bonding cover lenses or touch panel sensors to LCDs, the newest silicone LOCAs can offer increased cure speeds and highly advanced optical properties after RA testing. A 750-micron-thick lamination delivers a b* value of 0.3 for yellowing and 0.2% haze after 500 hrs QUV aging, with 50% less yellowing and 95% less haze when compared to traditional one-part silicone LOCAs.

The newest products in the silicone LOCA line, Loctite 5191™ and 5193™ silicone LOCAs and matching dam, Loctite 5191DM™, reportedly feature a patented chemical breakthrough that can radically increase cure speed and improve optical properties. While 5191 cures solely on exposure to UV light, it can be easier to handle in some lamination equipment. 5193 cures on exposure to UV and moisture, which can provide excellent cure in shadowed areas. The low-viscosity LOCAs are reportedly easy to apply and are designed for high-efficiency production processes, requiring 2,000 mJ of energy for full cure. 

Loctite 5192™ and its matching dam, 5192DM™, can be used in many high-volume display applications. UV-curable 5192 can cure with moisture in shadowed areas, protecting the display from problems with uncured adhesive such as bubbles, delamination, MURA and/or adhesive migration into the backlight unit of the LCD. The dual-cure capability reportedly ensures full adhesive cure and robust display performance, and eliminates the cure-through depth limitation of side curing and the work-in-process and potential LCD damage of heat curing.

For additional information, visit www.henkelna.com/loca.