8.3.4 Mixing systems

Static mixer: Principle of operation

Static mixers are available in various sizes (cross-sections) and lengths. Also available in round and square designs. The latter have the advantage of lower pressure loss compared to round designs.

It is important to use the correct mixer. This is usually delivered with the adhesive. If another mixer is used, it is advisable to consult the adhesive manufacturer about this. This is because mixing quality varies considerably when using apparently similar mixers from different manufacturers.

Inhomogeneous mixing of two adhesive components in the cartridge side of a static mixer.

Source: KLEBTECHNIK Dr. Hartwig Lohse e.K.

Dynamic mixers:

Dynamic mixers are not disposal as are static mixers. Rather, they are relatively expensive precision devices.

Dynamic mixers must be carefully rinsed to avoid adhesive residues remaining behind in corners. etc.. Use either a solvent or aqueous cleaning agent for this. The mixer must be carefully dried after cleaning with aqueous cleaning agents, and this is particular so when processing polyurethane adhesives.
At regular intervals dynamic mixers must also be totally disassembled and thoroughly cleaned. For this period a substitute mixer may be required.

In some cases dynamic mixers are the only solution for 2-C adhesives with short pot lives and/or for small adhesive quantities per “fill”.