In a recent blog, we discussed general considerations to make when painting high performance sealants. We detailed that high performance sealants:
- Meet or exceed industry specifications/accreditations
- Produce lower volatile organic compounds (VOCs)
- Offer greater elastic bonding capabilities
- Have high elastomeric properties
Now, let’s take a look at the paintability of certain high performance sealants based on their technologies:
High performance polyurethane sealants provide a tenacious bond with great tear resistance while maintaining elastic properties. Once cured, these sealants can be painted with high quality acrylic latex paints.
- What to Keep in Mind When Painting High Performance Polyurethane Sealants
It is recommended that a high performance polyurethane sealants cure for at least three days prior to painting.
Additionally, these sealants are moisture reactive. As a result, it’s important to not introduce copious amounts of water (from the paint). Doing so can cause these sealants to “flash cure”, which increases the potential for surface bubbling.
If using an older high performance polyurethane sealant, a thorough solvent wipe down should be performed to remove any dirt, chalking or surface contaminants.
Bostik 915 is an example of a high performance polyurethane sealant. The first and only product on the market, 915 is Miami-Dade Country Product Control Approved as a roofing sealant and roof tile adhesive. It also has adhesion to Kynar® resin-based coatings and a best-in-class warranty.
Hybrids are a general category of high performance sealants and are comprised of technologies including Silyl Modified Polymer (SMP), Silylated Polyether (SPE) and Silylated Polyurethane (SPUR). Like high performance polyurethane sealants, using high quality acrylic latex paints offer the best results.
- What to Keep in Mind When Painting High Performance Hybrid Sealants
High performance hybrid sealants do not require as much cure time as polyurethane sealants. This aspect allows contractors to complete their work sooner. However, it is important to first allow a good skin to develop prior to painting. This skin prevents deformation in the sealant joint surface.
Bostik Pro-MS 50 is a high performance hybrid sealant. Ideal for windows, doors, facades and siding, this product has adhesion to Kynar resin-based coatings and AAMA certification.
High performance silicone sealants are more difficult to paint and are considered slippery. Traditionally, paint does not perform well over the long term as a result.
While these high performance silicone sealants are marketed as “paintable”, it’s important to note that performance comprises may occur vs. polyurethane and hybrid sealants. As a result, it’s recommended to fully review and understand performance requirements prior to choosing whether or not to paint.
Bostik manufactures 1200, a high performance silicone sealant that offers superior adhesion to substrates such as glass, metals, ceramics and most plastics. It has excellent weathering properties and can withstand the harshest atmospheric conditions.
For more information on Bostik’s sealants, visit www.bostik-sealants.com, or call 800-7-BOSTIK.