Adhesives Industry Information

Adhesive manufacturers and adhesive suppliers offer a wide assortment of products for temporary and permanent bonding, encapsulating, laminating and sealing. To buy or have manufactured the most effective adhesive for a certain situation, consider the type of material to which it needs to bond and the type of bond strength necessary for the duration and demands of the application. Searching for the right adhesive can be quite a task because the kinds are so various and new innovations are continuously forthcoming.

Adhesives can come as one-part or two-part formulas. Two-part adhesives consist of two separate components that need to mixed (some come pre-mixed) or applied to separate adherends and pressed together to create a chemical reaction leading to their bonding properties. One-part adhesives have latent bonding properties that are activated in various ways depending on the type of adhesive. Activation methods for adhesives include heat, addition or loss of water or a different solvent, pressure and lack of oxygen, as in anaerobic adhesives.

Adhesives can have differing setting temperatures ranging from above 212 degrees F to below 68 degrees F, depending on how much they need to be either cooled or dried to harden. For example, hot melt adhesives are activated to viscous liquid states at elevated temperatures and set when cooled. Adhesives have various setting speeds, some remaining tacky for a certain amount of time allowing parts to be assembled. Adhesives that have residual tack offer repositioning options. Once harden some adhesives can not be softened with heat; these are thermoset adhesives. However, some can be softened due to temperature change or moisture contact, so care must be taken when selecting an adhesive for these more demanding applications. Adhesives also vary as far as bond strengths. They can be measured by tensile strength, wet strength, impact strength, fatigue strength, cleavage strength, peel strength and shear strength.

Adhesive manufacturers and adhesive suppliers can offer products in the forms of solids (hot melt sticks, powder, granules, pellets, chips, etc.), liquids, pastes, foams, films or aerosol sprays. Film adhesives offer a uniform glueline, are activated by heat and/or pressure and come with or without release paper. Laminating adhesives are common film adhesives. A gap filling adhesive can be utilized as a sealant because it does not shrink much when set. Adhesive manufacturers and adhesive suppliers often sell application products such as hot melt glue guns and dispensers. Application methods include spreading with a tool or brush, spraying, dispensing through a nozzle (as in hand-held squeeze bottles, caulking guns or complex air-actuated or electric-actuated nozzles), roll coating, transfer printing, screen printing, curtain coating and application as a solid as with pressure sensitive or heat-activated film adhesives.