26 августа, 2015 
Pokraskin Some substrates, for example paper, cork, cardboard, leather, dichromated metals and some fabrics, can be slightly acidic and this surface acidity will result in a very slow cure or in some circumstances inhibit curing completely.
For these acidic substrates, a surface insensitive grade of cyanoacrylate must be used to ensure proper cure. The surface insensitive grades include special additives that can convert surface contamination into an activating species towards cyanoacrylates and then allow the adhesive to continue curing in the usual way. Such ‘surface insensitive’ cyanoacrylates are good general-purpose bonders — making them particularly suited to applications where the condition of the substrate is not well defined.
This additive is now used in some consumer grades of ‘super glue’ because it reduces the dependence on surface moisture to cure and ultimately leads to good bond strength on many substrates.
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