One-Way Stick vs Two-Way Stick Adhesives – What’s the Difference?

One-way stick and two-way stick adhesives have different properties. It is important that you know the difference for product selection.

What are one-way stick adhesives?

One-way stick adhesives are generally VOC free (solvent free) products, such as moisture-curing polyurethane or two-part polyurethane adhesives.

These types of adhesives are curing products, which turn from a liquid to a solid via their curing mechanism. Moisture-curing adhesives react with moisture in the air/substrates to cure. With two-part adhesives, it is the reaction of the individual parts mixing that causes the curing process.

Water based products can also be used as a one-way bond, however one of the substrates must be porous to allow the water to evaporate from the bond line.

Ensure good consolidation of the substrates, using a roller, to ensure the adhesive transfers to the non-coated substrate and full contact is maintained during the cure cycle of the adhesive to achieve the maximum bond strength.

Curing adhesives offer weatherproof bonds, with economical coverage rates and quick and simple application.

What are two-way stick adhesives?

Two-way stick adhesives are otherwise known as contact adhesives. These adhesives are generally solvent based (contain VOC). The adhesive is applied to both surfaces that are being bonded (for example, the substrate and membrane). Time is then allowed for the adhesive to dry or solvent to evaporate before the coated surfaces are put together.

Care should be taken to ensure the bond is made within the tack life of the adhesive. Always ensure good consolidation, using a water-filled roller (or hand roller for detail areas), to ensure the two adhesive layers are in full contact to achieve the maximum bond strength.

Contact adhesives have a high initial strength and will produce an immediate bond.

Our infographic below summarises the key points: