"The semi-flowable nature of this material allows it to seal very complex extrusion profiles without the need for tooling," explained Dow Corning Market Specialist Doug Kempf. "It's an ideal narrow-joint seam sealer, providing a barrier against air and water in window-sash or frame components that are mechanically fastened, mitered or slip-jointed.
"Because of its high extrusion rate and fast, room-temperature cure, the product is ideally suited for high-speed manufacturing," Kempf added. The flow rate of >700 grams per minute allows easy pumping, and a skin-over time of just 10 to 15 minutes at room temperature facilitates optimum line speeds.
Unlike the solvent-based acrylics commonly used today, which contain 30% to 50% solvent, the new Dow Corning formulation is supplied at >97% solids. That translates to less shrinkage, significantly reduced emissions and few flammability issues.
Kempf explained that although acrylic sealants offer excellent adhesion, they don't fully cure in place. Over time, high temperatures can cause this type of formulation to sag, and it may develop gaps that lead to water leaks. With the acrylic formulations, low-temperature flexibility is also a recognized problem.
In contrast, Dow Corning 1199 SSL silicone sealant cures to a tough, resilient elastomer that effectively withstands UV exposure, extreme temperatures and thermal movement to provide a durable, weathertight seal. The new silicone material has demonstrated excellent performance with poured and debridged urethane designs.
The product's neutral-cure system is based on a non-corrosive formulation that offers primerless adhesion to most fenestration materials and releases no objectionable odor. The cured elastomer exhibits 135-psi tensile strength and 375% elongation, allowing it to easily accommodate extreme thermal cycling and normal substrate movement. Its service temperature range is -60 deg F to 300 deg F (-51 deg C to 149 deg C).
The silicone sealant is available in five standard colors: clear, white, black, bronze and aluminum. It is supplied in 10.3-oz cartridges, 5-gallon pails or 55-gallon drums.
Dow Corning develops, manufactures and markets a range of silicon-based materials. Currently offering more than 10,000 products to customers around the world, the company is a global leader in silicon-based technology, with shares equally owned by The Dow Chemical Co. and Corning Inc.
For more information, contact Dow Corning Corp., PO Box 0994, Midland, MI 48686-0994; phone 517-496-6000; fax 517-496-8026; or visit www.dowcorning.com/construction. Or Circle No. 72.