Cyanoacrylate, curing volume

Activators are often required where the cyanoacrylate needs to be cured through a large volume or where there is adhesive outside the joint line. Unlike primers, activators do not improve the adhesion, but improve the cohesion of the cyanoacrylate by guaranteeing proper curing. 

Slow cure may also be due to a thick bond line (adhesive >0.2 mm). Cyanoacrylates are most suited to applications where the bond line is less than 0.1 mm thick although a cure through a volume up to several mm is possible using UV curing cyanoacrylates. 

Anerobic adhesives. Acrylate acid diester and cyanoacrylate resins are called anaerobic adhesives because they cure when air is excluded from the resin. Anaerobic resins are noted for being simple to use, one-part adhesives, having fast cure at room temperature and high cost. However, the cost is moderate when considering a bonded-area basis because only a small volume of adhesive is required. Most anaerobic adhesives do not cure when gaps between adherend surfaces are greater than 10 mils, although some monomers have been developed to provide for thicker bond-lines. 

In the electronics industry, the list of commonly dispensed fluids includes adhesives (anaerobic, cyanoacrylates, epoxy, and UV) conformal coatings flux (liquid and paste) RTV silicone (room-temperature vulcanization — curing without heat) solder mask, and solder paste. Given the vast differences in the properties of these fluids, in particular their viscosities and typical dispensed volume, dispensing... 

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