As building codes shift in favor of materials that offer greater efficiency and better performance, manufacturers of building envelope flashing tapes are reassessing the adhesives they use to meet the expectations of contractors and builders.
UV-cured acrylic adhesives in particular are increasingly attracting the attention of flashing tape manufacturers, as these adhesives offer better overall performance and longer lifespans than rubberized asphalt and synthetic rubber adhesives. To understand why UV-cured acrylic adhesives gaining more prominence over more traditional adhesives used in flashing tapes, it helps to look at three key performance aspects that have a direct impact on product lifespan: temperature range, ease of application and energy efficiency.
Building envelope product manufacturers typically choose from among three types of adhesives for their flashing tapes: rubberized asphalt, synthetic rubbers and UV-cured acrylics. For years, rubberized asphalt has been the default adhesive for flashing tapes — a choice that is generally attributed to the lower cost of the material. But the low cost also comes with a narrower temperature range of 40 F (4 C) to 180 F (82 C). This tight range has a direct effect on the adhesive’s ability to bond in temperatures outside of the range, which can have adverse effects in geographic areas with climates that exceed these temperatures.
The temperature limitations of rubberized asphalt have led some flashing tape manufacturers to use synthetic rubbers, like butyl rubbers and block copolymers, to accommodate customers working in locations with more extreme temperatures. Synthetic rubbers, however, only offer a slightly broader temperature range than rubberized asphalt, performing at 30 F (-1 C) to 200 F (93 C). This still leaves builders in some climate zones without a high-performance flashing tape solution.
UV-cured acrylic adhesives help solve the problem of building in extreme temperatures by offering the broadest range of the three: 0 F (-18 C) to more than 240 F (115 C). This range ensures flashing tapes can deliver a strong bond in wide range geographic locations and climates. It also has the benefit of extending the construction season, as building envelope work can continue longer into the colder months while the flashing tape remains workable.
Ease of Application
For flashing tapes, a direct benefit of the broader temperature range of UV-cured acrylic adhesives is the ease with which they can be applied. Even in colder temperatures at the low end of the range, UV-cured acrylic adhesives remain highly workable and allow builders to peel up and reposition flashing tapes when installing roof underlayment, water-resistive barriers and other building envelope components. This enables contractors to improve energy efficiency by getting the best surface contact and optimal adhesion to substrates and openings such as windows, doors and vent pipes.
Flashing tapes that use UV-cured acrylic adhesives also provide the highest level of adhesion across a wider range of substrates — including those with low surface energy, such as vinyl, polyethylene, polystyrene, polypropylene, ABS plastic, wood and more. UV-cured acrylics also achieve strong adhesion without the use of a primer, which offers contractors and builders time and money savings in the installation process. In addition, UV-cured acrylic adhesives are free of solvents and volatile organic compounds and can be used with other products that may react with solvents, making them safer for workers and the environment.
Because builders have greater control with workable, flexible flashing tapes that use UV-cured acrylic adhesives, they can achieve a better fit and consistent adhesion. UV-cured acrylic adhesives form strong bonds using highly crosslinked polymer chains that maintain their stability, even in extreme temperatures. Bond strength directly contributes to airtight and watertight seals, thereby protecting the integrity and performance of the building envelope against the elements. And while exposure to repeated cycles of temperature fluctuation may cause flashing tapes with rubberized asphalt or synthetic rubber adhesives to shift out of place, the strong bond of UV-cured acrylic adhesives also prevents material migration after installation.
Flashing Tapes No Longer Limited
For years, contractors and builders worked within the limitations of flashing tapes that used rubberized asphalt or synthetic rubbers. Now, the introduction of UV-cured acrylic adhesives means they no longer have to settle for sub-par performance that can require costly rework or damage their reputation.
Contractors can enjoy a wider window of time for building envelope construction, greater control of flashing tape application and stronger bonding that ensures their materials will stay in place to protect their work and their reputations for years to come.
Learn more about the benefits of UV-cured acrylic adhesives for building envelope products here.