Everything about Contact Adhesives

These are one of the most common type of adhesives used in home and commercial projects in applications where two broad, flat and closely fitting surfaces are to be bonded together. At our homes plastic laminate countertops in kitchens are glued together using contact adhesives.

The unique property these adhesives carry allows them to stick to themselves even after a period of time when adhesive is no longer tacky. Therefore, it makes them great choice for gluing nonporous materials together.

They are also widely known as “contact cement” and they serve a special purpose as they offer high initial strength and are polymer-based adhesives. High initial strength makes them suitable for laminating applications and assembling counter tops.

Both water based and solvent based versions of contact adhesives are available in market and selection can be done depending upon the sensitivity of the materials. Solvent borne contact adhesives contain flammable solvents which are evaporated in air and hence need to be handled cautiously. Either of these adhesives can be applied with brush, spray or a roller. Solvent borne contact adhesives dry faster as compared to water-based counterparts mostly within 15 minutes. However by increasing the air movement or heating drying time of water-based contact adhesives can also be reduced.

Application process

Contact adhesives are applied on both surfaces to be bonded together and left for a few minutes to become tacky (Solvent such as water is allowed to get evaporated) before bringing the surfaces together.  Coated surfaces are then brought together and they form an immediate bond. They can typically be rolled or pressed to ensure contact has been formed throughout the surface area. For the reason that adhesive has already dried before bonding they can be used to bond non-porous substrates having a large surface area.

Tech Tips on working with contact adhesives

 When bonding porous material with contact adhesive apply two coats allowing contact adhesive to dry in between the coats. First coat seals the porous surface and works as a primer and second coat allows room for actual adhesive properties to be exhibited by contact adhesive.

Solvent-borne contact adhesives are more tolerant to contamination on the surface and if the environment is dusty using a water-borne contact adhesive will reduce bond strength. 

Drying time of adhesive will depend upon the thickness of the adhesive been applied irrespective of the what is stated by manufacturer. If you bring the surfaces together before adhesive has dried you will not get any bond strength. It is always a good idea to touch and feel the adhesive has become tacky.  It essentially means when you touch the adhesive it seems sticky but it does not get transferred to your fingers. At this point of time adhesive can be considered to have dried enough to create a strong bond.

If the application of contact adhesive is even your drying time will be even as well and you will create a stronger bond between materials. To get an even build-up of adhesive on both surfaces it is an excellent idea to use a paint roller which can be washed with solvent and soapy water once you have finished your project.

Limitation

Utmost care is required when aligning the surfaces together as re positioning is nearly impossible with these types of adhesives. Hence there is no room for error while working with contact adhesives.