For example, polysulfide technology is often utilized in construction sealants, secondary containment sealants, and aerospace sealants, where the integrity of the product is critical to ensure that it does not fail, crack, erode, or break down during its life expectancy, even in environments with harsh UV and chemical exposure.
Like other high performing sealant chemistries, polysulfides provide exceptional mechanical properties, joint movement tolerance, and adhesion. However, they are differentiated by a range of unique benefits that are ideal for demanding segments, such as civil engineering, road surfaces, insulated glass, tank lining, and aircraft fuel tanks.
When these properties add value to an application, a polysulfide sealant should be selected over silicone, urethane, or silyl-terminated chemistries.
However, polysulfide sealants are also associated with some specific challenges. For example, they are considered relatively slow to cure and have a recognizable odor. In addition, regulatory agencies are scrutinizing the conventional plasticizers used in these applications due to potential safety concerns (primarily chlorinated paraffins and phthalates). Manufacturers need alternatives that improve the regulatory and safety profile of the sealant, without sacrificing on the critical performance features above. Some alternatives may result in issues with the performance. For example, they may have lower compatibility with the polymer, which can result in plasticizer migration and even sealant failure (loss of adhesion or flexibility, cracks, etc.).
Dibenzoates are widely known and have been used as non-phthalate plasticizers in sealants for decades. However, they have not been available as tailored solutions for polysulfides until recently.
Emerald Kalama Chemical introduced three new plasticizers as part of a new platform designed for two-part polysulfide sealants, available under the Kalama® VITROFLEX® brand. Kalama VITROFLEX B was developed for the “B” (catalyst) side, and Kalama VITROFLEX A90 and VITROFLEX A99 are both tailored for the “A” (polymer) side. They may also be used in one-part polysulfide sealants.
Together, these plasticizers provide a complete solution, enabling formulators to maximize the critical performance features and increase the value of polysulfide sealants.
Contact Emerald for more information about how to enhance these properties in polysulfide sealants, as well as other formulation guidance.