Surfactants are widely used in a range of adhesives and sealants, primarily to promote the wetting of surfaces to promote adhesion. Unfortunately, some of them have been found to have suspect toxicity profiles or environmental issues.

Solvent-based adhesives were traditionally attractive systems for both industrial users and consumers. They are low-cost systems that dry quickly and frequently give high performance, particularly on plastics where the solvents soften or dissolve the surface layers.

We assemble steel panels with welding and screws. Can we replace these with an adhesive?

It may be a one- or two-part system. We need temperature resistance up to 500˚C, and the adhesive will be applied to fill small gaps in a hot mild steel structure. The required initial setting time is 5 min.

You don’t indicate which substrate is on the outside, and this does make a difference in the possible choice of adhesive. Epoxy adhesives were traditionally used for this application, but they should be used with care as they may be too rigid.

You need to look at so-called “shadow curing” options. Most UV-cured systems are based on acrylates and methacrylates and cure free-radically by the decomposition of a photoinitiator.

All adhesives tend to lose strength on immersion in water. Water acts in two ways on a bonded assembly: It can be absorbed into the adhesive and soften it, and it can degrade the interface between the adhesive and the bonded surfaces.

The most desirable type of adhesive is one that sets quickly and has some heat resistance.

Bookbinding is an important application area for adhesives, and requirements are becoming more demanding.

Adhesives can be classified in several ways, including their material origin (e.g., natural or synthetic) and their type of cure (e.g., physical curing such as drying or chemical curing).