| Résumé : |
Today’s elastomeric joint sealants are quite remarkable. For a relatively low cost, they provide much of the protection against air or water intrusion for many types of assemblies. In these applications, a sealant must adhere tenaciously to the substrates and maintain prolonged flexibility while being bombarded by wind, rain, heat, ultraviolet (UV) light, ice, dirt, and so on. In many cases, the sealants are also expected to maintain their color.
Discoloration of paints, finished plastic components or sheets is a well-documented subject; however, it seems the same cannot be said of sealants. Granted, in terms of surface area in use, sealants account for a relatively small amount. Because of their location and visibility on many assemblies, however, any discoloration is readily apparent and often unsightly.
For the most part, the only solution to this problem is a costly rework of seams to replace any sealant. This may be done in vain, however, if the basic cause of the problem is not identified or understood and the discoloration returns at a later time. It is useful to understand the basic mechanisms by which sealants may eventually discolor. This information may enable formulators to improve their offerings and aid end users in choosing the appropriate sealants for their applications. |
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Discoloration of elastomeric joint sealants in ADHESIVES & SEALANTS INDUSTRY (ASI), Vol. 20, N° 4 (04/2013)
