Several recent advances in curing technology involve ultraviolet (UV) methods, but time-tested techniques also are improving and next-generation solutions continue to emerge.
Fast curing: New technologies increase cure speed, which puts floors back in service sooner. For instance, the EBECRYL 891 resin from Cytec is a UV-curable, modified polyester acrylate for concrete flooring applications. Each coat is cured instantly with the company’s on-site UV curing equipment, and the resin can be formulated with the company’s other UV-curable resin systems to achieve specific adhesion, chemical resistance and toughness properties.
Adjustable curing: Adjustable cure rates might be necessary when instant cure times aren’t ideal. The Polyurea 350 primer/body coat by Citadel Floor Finishing Systems cures in less than 24 hours, even with multiple application layers, using a patent-pending adjustable cure rate technology that increases consistency, improves coverage and reduces flaws. Suited for industrial maintenance and shop floors, the system increases stability by letting the material pre-cure to the floor before any aggregate is added, and installers can wet-out large surface areas before broadcasting.
Compared to traditional polyurea floor coatings, the Polyurea 350 has a longer pot life, giving installers more time to broadcast aggregate into the material. It has better flexibility, strength, adhesion and waterproofing properties than epoxy and it can cure rapidly at any temperature. In addition to concrete surfaces, the product can be applied as a primer coat on steel, wood, fiberglass and other substrates. The company warrants the product for as long as 20 years against delamination, cracking and peeling when a certified installer is used.
Solvent-free: Safe and environmentally correct floor coatings are solvent-free and comply with volatile organic compound (VOC) and hazardous air pollutant (HAP) mandates. A floor coating system that complies with VOC and HAP, has no solvents, is low odor and is nonflammable is Quaker Chemical’s RapidShield. This polyester UV-curable system is designed for use with new or existing concrete floors. It has a one-component formulation that requires no mixing.
Using proprietary QV Technology, RapidShield’s engineered lamp curing system delivers the specific wavelength, intensity and duration of UV light necessary for optimal curing. Photoinhibitors in the floor coating allow it to harden instantly when exposed to the mobile curing unit’s UV light
Chemistry: Reformulating proven resins adds new dimensions to the beneficial qualities of coatings. Stonhard is doing a lot of formulation work with polyaspartic urethenes, which cure rapidly and contain no VOCs. “Aspartic coating systems have very good chemical resistance and low odor. They cure quickly, so you can install multiple steps of the system in the same day, and have excellent UV stability,” says Jeff Beam, the company’s director of tech service. Stonhard’s Stontec UTF is a decorative, polyaspartic urethane flake broadcast system that resists stains, wear and chemicals.
The use of recycled glass in Stonblend GSI-G, an epoxy mortar system, helps customers achieve LEED certification points. The high-performance system has excellent wear, chemical, stain and mar resistance. The glass is showcased in the smooth, easy-to-clean floor surface.
Innovations underway: Researchers continually look for new ways to control, measure and accelerate curing while reducing the associated costs. For instance, scientists at Cytec’s Field Applied Lab near Atlanta, where the EBECRYL 891 resin was developed, are working on new UV-curable solutions for other hard flooring substrates, including wood, vinyl, concrete and tile.
Curing also plays a role in efforts to reduce concrete’s carbon footprint. Carbon Sense Solutions is performing industrial trials of its CO2 Accelerated Concrete Curing technology, which is said to reduce CO2 emissions and energy consumption while improving the mechanical properties of pre-cast concrete products. The technology uses carbonation to bubble CO2 through wet cement and sequester the gas. It eliminates the need for steam and the concrete is cured in an hour. By comparison, curing regular pre-cast concrete using steam can take from 12 hours to 24 hours. Whether this technology has potential for the shop floor remains to be seen, but the possibilities are intriguing.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at Sheila@addcomm.com.
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