RHOPLEX EC-3100 is an all-acrylic polymer designed primarily for use in pigmented elastomeric basecoats to provide adhesion to weathered TPO roofing membranes.
Elastomeric roof coatings (ERCs) have been used for many years as a cost-effective means of maintaining, repairing and extending the useful life of many types of commercial roofing substrates, including sprayed polyurethane foam (SPF), rubber [ethylene propylene diene terpolymer (EPDM)], asphalt, modified bitumen and metal. Until now, a major exception has been thermoplastic polyolefin (TPO) roofs, a popular roofing system first introduced commercially to the U.S. market in 1990.(1) As some of the earlier TPO roofing systems have begun to show signs of natural wear and tear, the challenge has been developing a viable waterborne (hydrophilic) elastomeric roof coating formulation with sufficient adhesion to the amorphous, water-resistant (hydrophobic) polyolefin surface of weathered TPO roofing membranes that also meets ASTM performance standards and withstands harsh outdoor environments.
This article describes highlights of the ongoing laboratory, outdoor exposure and pilot testing of various acrylic polymer emulsion and additive combinations for use on weathered TPO roofing systems. The weathered TPO adhesion challenge was overcome by using a hydrophilic polyacid dispersant, matching the contact angle of the formulation to that of the weathered TPO surface, and by incorporating three separate adhesion technologies to create an acrylic polymer emulsion binder, which ultimately can be used to manufacture an elastomeric roof coating with exceptional TPO adhesion.
After nearly three years of field testing using two formulation prototypes at three different sites, the successful acrylic polymer emulsion was commercialized as RHOPLEX™ EC-3100. The new binder opens the door to manufacturing elastomeric roof basecoats that fully adhere to TPO substrates and cost-effectively extend the useful life of ageing TPO roofing systems by five to 10 years or longer.