3.3.1.7 Storage

The adhesive contains acidic stabilizer, and when adhesive was applied to a substrate surface, the acidic stabilizer that keeps the adhesive stable reacts with moisture on the surface. As the acidic stabilizer is consumed by moisture on the surface, the adhesive becomes unstable, and monomer reacts to each other, and the negative partial load is then passed to the next monomer in a chain reaction as seen

The polymerization continues until no monomer is available or a molecule with

The rule of thumb for CA adhesives such as the lower the viscosity, the faster the curing speed; the higher the viscosity, the slower the curing speed, and it generates while curing(exothermic reaction); the thinner the bond line, the faster the curing time, and the bigger the package size, the longer the shelf life, and not recommended for glass or glazed ceramics, and not ideal for a large area bonding, and liquid monomer can cause a stress crack on some sensitive plastics, and some

To achieve the fastest cure to handling strength, a "zero gap" condition is

The best results are achieved when the relative humidity in the working environment is 40–60% at room temperature. Lower humidity leads to slower curing; higher humidity accelerates it but may impair the final strength of the bond. Longer cure times, however, slow down production. With the help of a humidity control system, favorable humidity levels can be kept constant in the bonding workplace.

Acidic surfaces (pH value <7) may delay or even prevent curing, whereas

in Figure 6 [12].

Figure 5.

Figure 6.

CA anionic reaction 1.

CA anionic reaction 2.

3.3.1 General characteristics

product may cause a blooming.

3.3.1.2 Cure versus bond line

3.3.1.3 Cure versus moisture

3.3.1.4 Cure versu surface pH

alkaline surfaces (pH value >7) accelerate curing.

desirable.

78

3.3.1.1 Rule of thumb

positive partial load (e.g., stabilizer) is reached.

Adhesives and Adhesive Joints in Industry Applications

The proper storage of cyanoacrylate adhesive is crucial for the best product shelf life. Refrigeration (4C) in an unopened state is recommended. If adhesive bottle opened already, it is recommended to close the bottle tightly and keep it at room temperature and continue to use it. It is not necessary to be refrigerated.
