How to stabilize cyanoacrylate adhesive?

Cyanoacrylate binder is a monomer binder. They are based on an ester of a – cyanoacrylate. This vinegar can be polymerized by free radical and anionic polymerization. In this case, anionic polymerization can be caused by tiny amounts of water found on almost any surface. As a result, cyanoacrylate adhesives solidify rapidly when introduced between two surfaces stored under environmental conditions.

In terms of adhesive technology, the particular advantage of cyanoacrylate adhesives lies precisely in their speed of reaction and the high bond strength they form, especially when using polar substrates. However, stabilizers must be added to the production and storage of adhesives. A system of stabilizers must be selected so that polymerization does not occur in sealed drums during transport and storage, even at high temperatures and after long periods of time, otherwise, polymerization will occur immediately after application. Therefore, in addition to the known free radical polymerization inhibitors, cyanoacrylate binders are often added to inhibit anionic polymerization.

For example, in DE-OS 21 00 026 it is proposed to add a strong acid cation exchanger as an inhibitor. Among them, the cation exchanger based on crosslinked polystyrene containing sulfonyl group is preferred. The disadvantage of this method is that the added ion exchanger can easily impede the outflow of the adhesive, and, as a solid, the ion exchanger cannot operate through the entire volume of the adhesive

In German patent application DE4109 105, surface modification of cyanoacrylate adhesive storage container was proposed to contain acid groups. Although this suggestion can be successfully implemented, there is a problem here, which is that the inhibitor effect only occurs near the walls of the container.

Another way to stabilize cyanoacrylate binders is to add sulfur dioxide as an inhibitor. Although this measure has been successfully applied in practice, it is worth noting that sulfur dioxide is a gaseous substance, so it is difficult to add it uniformly, with the accompanying result that mass changes will occur. In addition, sulfur dioxide can escape from the adhesive container by diffusion during storage.