By Frank Esposito, Plastics News
Akron, Ohio -- In the plastics market, Innovative Polymers Inc. and Rock Candy LLC are real rock stars.
Innovative Polymers -- a polyurethanes systems maker in St. Johns, Michigan -- and Akron, Ohio-based open-cast moulder Rock Candy have joined forces to make a new line of PU climbing holds used in indoor rock climbing.
In the US, almost 8 million people participate in indoor climbing each year, recently pushing the sport in popularity past outdoor climbing as a recreational activity. Indoor climbing also is being recognised as a sport by a greater number of national and international competitions, according to officials with both firms.
The climbing holds made with Innovative's material are multi-textured and ultra-durable. They come in a variety of shapes and sizes that simulate real rocks and boulders.
Rock Candy first contacted Innovative in 2007 while searching for a material for its products. The challenge, according to Innovative president Mike Molitor, was to create a material that could handle a lot of stress -- from climbers pulling with all their weight -- that also was easily formed and pigmented to be attractive to users.
"We have a standard line of products, but this was a case where the customer had their own criteria," Molitor said by phone 28 July. "It's not a large application by volume, but it's one that shows what we can do and that shows where we fit in niche markets."
"When we were looking for a material, we had a few different goals," said Rock Candy owner Nathan Yokum. "We wanted durability -- something that could be dropped without breaking -- and we also wanted something with flexibility and with some give to it."
Rock Candy tested material from several suppliers before choosing Innovative. The moulder now has a list of about 100 regular customers, ranging from commercial gyms to rock climbing fans who have installed walls in their homes. The firm puts out new types of holds three times a year and handles international sales through a third-party distributor.
The holds range in size from a 1-inch base to those measuring 28 inches by 18 inches and are 6 inches deep. Each new mould design is carved out of PU foam, with the resulting pattern used to build single-cavity or multicavity silicone rubber moulds.
After the moulds are fully cured, their surfaces are coated with a release agent. Parts then are poured and allowed to cure for about an hour at room temperature. The type of PU used in the holds has gel time of seven to nine minutes.
Colouring also is important, since climbing course designers use the colours to map out climbing routes. The colours on the holds also have to hold up after being cleaned to remove chalk residue and other contaminants.
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