24 сентября, 2015 
Pokraskin Methyl esters of cyanacrylic acid are used to generate fast-curing, high-strength cyanoacrylate adhesives for metals, while ethyl esters are used to generate adhesives for metals and plastic materials. In order to overcome problems with the odor ofthese two monomers, higher esters are employed. but these lead to the generation of adhesives with lower strengths and longer curing periods. Crosslinking agents based on bifunctional cyanoacrylates can be used to improve the thermal resistance.
All of these monomers have a low viscosity that may in time cause problems with absorbent adherents and vertical applications. Consequently, up to 25% thickener may need to be added, mostly as polymers such as PMMA or PVA. The additional incorporation of hydrophobic pyrogenic silicic acid results in a formulation that provides for structural viscosity, easy processing on vertical surfaces, improved bonding of absorbent surfaces, and enhanced gap-filling characteristics. Due to their high Tg-values, cyanoacrylate adhesives are very brittle, but the impact resistance can be improved by adding 10-15% of an elastomer such as acrylonitrile — butadiene-styrene (ABS) copolymer.
The polymerization of cyanoacrylate monomers takes place very easily, both in the form of anionic and radical polymerization. To prevent uncontrolled reactions and too-short a storage life, acid stabilizers such as sulfur dioxide or phosphoric acid, and radical scavengers such as hindered phenols, are used. Owing to its gaseous condition, sulfur dioxide is released immediately after application of the adhesive and joining of the adherents. This stabilizer therefore provides for a quick onset of polymerization, which is a desirable feature in many cases.
A typical formulation for a cyanoacrylate adhesive contains 88% cyanoacrylate monomer, 9% thickener, 3% rheological additive, and 0.02-0.03% acid or radical stabilizer.
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