In Alberta, Canada, AOC LLC provided Chemposite Inc. two different formulations of its Vipel® resin for a facility that moves hydrochloric acid from trains to transport trucks. The Vipel F010 resin, included in the structural layer of four fiberglass surge capacity tanks, is a premium bisphenol-A epoxy vinyl ester. It offers a good balance of corrosion resistance and processability, according to AOC. For the tank liners, Chemposite chose Vipel F085, an epoxy novolac vinyl ester resin, because of its organic solvent resistance and high-temperature properties.
Belco Manufacturing Co. Inc. employed another AOC Vipel resin, K022-C vinyl ester, for the manufacture of carbon adsorption vessels for a wastewater treatment plant in Birmingham, Ala. The adsorbers are part of the plant’s odor abatement system, which removes hydrogen sulfide from select points throughout the system. With the corrosion-resistant resin, the composite vessels are able to resist long-term exposure to the moisture-laden hydrogen sulfide environment. The vessels and ducting also had to meet E84 Class 1 flame spread requirements.
There are fewer polymer categories for flame and smoke-inhibiting resins. Most come from vinyl esters (including brominated epoxy vinyl ester); polyesters (including brominated polyesters); and modified acrylics (non-brominated).
Bromine was one of the first fire-retardant technologies in the composites industry. Fabricators initially used brominated polyester resins but eventually moved to brominated epoxy vinyl ester resins because of their better mechanical properties.
While bromines limit the spread of fire, they can also give off a lot of deadly smoke. This is a problem in areas where there are a large number of people but limited exit options (movie theaters, railway cars, etc.). In response to these concerns, resin companies have developed non-brominated fire-retardant products.
Ashland offers non-brominated, modified acrylic resins under the Modar™ label. Mass transit vehicles and rail cars throughout Europe include interiors made with Modar resins. Composite Panel Systems also used a next-generation Modar resin in its innovative Epitome composite foundation wall system.
“The chemistry was specifically designed to replace poured concrete in residential foundations,” says Thom Johnson, Ashland’s market manager for specialty resins. “The structure is a foam-filled sandwich panel that gives three times the tensile strength of concrete walls and has really good fire retardant properties.” Built offsite, the Epitome panels are shipped to a job site and dropped onto concrete footers in the foundation hole. A poured concrete foundation typically takes seven to 10 days to complete; with Epitome, it takes just a few hours to finish a fire-retardant foundation. The wall system passed the National Fire Protection Association’s 286 room corner burn test and therefore doesn’t require a thermal barrier, such as drywall, prior to occupancy.