It took Isotec International many years to perfect a polyurethane that could replace the typical polyester resin used to back hot tubs.
That hard work, which resulted in the invention of Acrylobond in the late 1990s, seems to have paid off for Isotec, a Canton, Georgia-based company that specializes in producing chemicals and polymers for a variety of industries around the world.
Forest Knight, Isotec’s president, says that, among the many reasons they developed Acrylobond, “No. 1 in our minds was the environmental issue.”
Traditional polyester resin contains styrene, which Knight maintains is problematic because styrene gets released into the air when the polyester resin is sprayed on the hot tub. It’s nasty stuff, Knight says. In fact, the International Agency for Research on Cancer has determined that styrene is a possible human carcinogen.
Another benefit is that Acrylobond is not just safer, but also easier to apply, says Knight. Applying polyester resin to a hot tub can be a labor-intensive process: It requires numerous workers to hand roll the fiberglass fibers for reinforcement, followed by a lengthy cure time. Isotec’s use of polyurethane instead means there’s no rolling required, and it can be done by a robot.
For Timothy Lust, director of Lewisburg, Pennsylvania-based hot tub manufacturer Strong Spas, his company chose Isotec’s product for its durability and the increased production-cycle time, allowing for a faster product flow through manufacturing for the end customer. However, the product’s minimal environmental impact may have played an even bigger role in their decision.
“The increased use of Acrylobond will continue to reduce the air pollutant emissions for a much more environmentally friendly product,” Lust says.
Using Acrylobond in place of polyester resin to coat hot tubs could be a positive shift for the industry as well as the health of workers. Besides lacking styrene, Knight says the product is 100% reactive, meaning all the chemicals in it react — leaving nothing to go into the air during the application process.
“Our [process] is really, really fast,” Knight says. “We can control that.”
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What they can’t control is the cost, says Knight. For Isotec the cost of polyurethane was the main roadblock in the development process. But Knight says Isotec was determined to find a solution as the company felt that creating a product that could save manufacturers time could prove invaluable.
“It took us a while as a company to come up with a value proposition,” Knight says. “The throughput of making [a spa] out of polyurethane or Acrylobond as opposed to polyester resin is that ours is so much faster. It’s 10 times faster just in curing. That is a big deal.”
While Acrylobond material costs might be higher, the trade-off, according to Knight, is that manufacturers see savings in labor. The product has no Volatile Organic Compounds (VOCs) that require special permits. Additionally, according to Lust, it provides better material strength with greater consistency, since hand rolling is no longer necessary, eliminating additional costs caused by human error.
Finally, the faster application process with Acrylobond, may help ease the backlog many manufacturers are experiencing from 2020, which means being able to get more spas in the hands of dealers.
Strong Spas is just one of 12 manufacturers that have switched to Acrylobond since its creation more than 24 years ago, but as the need for faster production times grow, Acrylobond is likely to be adopted by even more manufacturers in the coming years.
Bullfrog Spas, which is headquartered in Herriman, Utah, is another manufacturer using Acrylobond in its hot tubs.
“As a U.S. manufacturer, it was important to us to choose an acrylic backing system that provides our customers optimal spa shell strength and longevity while limiting any negative impacts to our employees and the environment,” says Dan Sjoblom, Bullfrog Spas executive vice president. “This material can help further modernize spa manufacturing by providing a sustainable path to optimal safety, precision and speed.”