When it comes to commercial sealants, manufacturers offer a wide variety of products to meet specific production needs. Generally, these products are compromise formulations designed to address the majority of common application standards and requirements.
The physical and chemical properties of a sealant are important, but the overall ability of a product to withstand a specified set of conditions is critical. This includes a joint’s movement capabilities, the practicality of installing the product, environmental exposure considerations and even its aesthetic appearance.
In addition, the ability of a sealant to bond well to different substrates is important. This can be influenced by a number of factors including surface preparation, the use and curing of primers, movement considerations and other variables. Most importantly, the ability of a sealant to hold up to a specified dead load is crucial. A failed sealant joint can significantly impact the performance of a building envelope and its contents. The cost of selecting and applying the right products for a particular application is repaid many times over by avoiding expensive repair and replacement costs later on.
Many Sealant manufacturers offer a range of polymer chemistry types, from silicone to high-performance acrylates, and a host of additives. Within a given polymer type, there can be substantial variations in capability and properties, so it is important to select the correct product for an application.
Adhesion is an important consideration for any sealant, but it is particularly vital in industrial applications where a sealant may be subjected to water exposure and temperature extremes. These conditions can negatively affect the performance of a sealant, which could result in premature failure or leakage. Specifiers must be aware of these limitations when specifying a sealant and ensure that proper surface preparation and the appropriate substrates are selected.
The ability of a sealant to resist weathering is also an important consideration, particularly in outdoor applications. The degree to which a sealant can resist environmental elements is usually determined by its base polymer, but can also be augmented with additives that improve performance in certain conditions.
Safety and health considerations are also often a factor for sealant selection. For example, some sealant formulations may react with the substrate or evaporate solvents to release toxic fumes or heat. Such concerns may be addressed by selecting low-reactivity or solvent-free formulations.
Shrinkage is another issue that can influence sealant performance. Excessive shrinkage on curing can result in internal stresses and voids in a sealed joint. This is especially true of aqueous and solvent-based sealants that shrink on conversion from a liquid to a solid state.
A manufacturer’s history of a sealant performing well in an application is an important factor to consider, as is their warranty information. This is particularly important in industrial applications where failures of adhesive and/or sealant joints can have significant economic consequences. In addition, a manufacturer’s technical support can be helpful in selecting the best product for an application. For example, a manufacturer can provide data on the amount of dead load that a product can withstand without exhibiting adhesive or cohesive failure (creep rupture). This information can help reduce the likelihood of unscheduled downtime due to sealant failure in an industrial environment.