Polymers, plastics, and composite materials are virtually everywhere in building construction. From wiring and plumbing fixtures to wall panels, siding, roofing, and decking, polymers provide versatile and durable construction materials.
When builders and contractors choose the polymer-based materials they use, flame retardancy is a primary concern. Some polymers, such as polypropylene or polyethylene, are highly flammable when they are unprotected, allowing flame to spread quickly. Others, such as polyvinyl chloride (PVC), are less flammable but release dense, toxic smoke in a fire. And, when polymers melt and drip, they can increase the spread of the fire.
Promoting fire safety in polymers, plastics
Building codes, such as the International Building Code (IBC) and International Residential Code (IRC), regulate polymers and plastics in construction—including requirements related to fire safety. Traditionally, plastics manufacturers have used antimony oxide (or other high-cost flame retardants) as a synergist to enhance the fire retardancy of halogen-containing polymers.
However, as manufacturers look for continuous improvement in product performance—and cost reduction in producing them—they have turned to alternatives for improving smoke suppression and fire retardancy in modern homes and offices, including in:
- Foam insulation
- Roofing membranes
- Skylights
- Interior finish and trim
- Caulks, sealants, and epoxy resins
- Wiring and cables
- Electrical connectors and bobbins
- Circuit breakers and housings
- Fabric and upholstery
- Carpet backing
- Wall coverings
- Light covers and wall panels
- Epoxy
Borates, alone or in combination with other inputs, is one such alternative that provides a better solution.
How do borates improve fire safety?
Borates, like those in U.S. Borax ammonium pentaborate and our Firebrake® family of products, provide increased value because they have synergistic effects with halogen and a variety of halogen-free systems, such as metal hydroxides, nitrogen and phosphorus compounds, and silicon-based flame retardants.
Borates help enhance fire safety in the following ways:
Flame retardancy
When heated to a decomposition temperature, the polymer structure breaks down. This breakdown produces volatile gases, which also burn and radiate heat back onto the polymer—literally adding fuel to the fire and intensifying the burning process.
Adding a zinc borate such as Firebrake ZB during manufacturing changes the polymer composition and interferes with the combustion process, reducing the likelihood of fire.
If a flame does ignite, Firebrake ZB forms a protective vitreous layer. This strong layer reduces the degradation rate of the polymer, helping prevent volatile gases from igniting and reducing dripping and flame spread.
Smoke and afterglow suppression
Firebrake products suppress smoke and afterglow (smoldering combustion) in a multitude of materials used throughout homes and offices.
Char promotion
Borates promote the formation of char, which helps to reduce the spread and duration of fire and helps to protect wiring and prevent short-circuiting and sparking.
Firebrake for fire retardancy across industries and applications
As a multifunctional flame retardant and smoke suppressant, Firebrake products are used in a variety of polymer and plastics applications:
- Sealants (flooring, trim, cables, piping): Helps prevent the spread of fire through intumescence (when a sealant is heated in the type of temperatures produced by a fire, it expands into openings between doors, cables, and pipes)
- Epoxy (flooring, trim): Helps retard flame and suppress smoke and afterglow in halogenated and nonhalogenated epoxy adhesives. Firebrake ZB displays synergy when used with ammonium polyphosphate, alumina trihydrate, or silica in halogen-free epoxies.
- Polyvinyls and polyesters (wiring and cables, piping, flooring, roofing, trim): Helps protect wires, cables, flooring, roofing membrane, and foamed insulation made from PVC, nylon, epoxy, polyethylene, polypropylene, polyesters, thermoplastic elastomers, and rubbers
- Other plastics (insulation, carpet, roofing): Firebrake is also used in plastic and rubber compounds
Cost-effective materials for cost-effective construction
Firebrake products can replace a portion or all of the more expensive antimony trioxide in halogen-containing formulations; Firebrake ZB can suppress smoke formation even when antimony oxide is present.
In addition to being an economical additive, Firebrake products can help manufacturers manage overall production costs. They have a refractive index that is similar to most polymer systems which means that when they are added to the polymer formulation, they help retain translucency, enabling low pigment loading while maintaining true color.
Using materials that meet fire safety standards—not to mention impart benefits such as energy efficiency and resistance to temperature and humidity fluctuations—is a smart move for builders.
Quality you can count on
Firebrake products are made from high-quality refined borates to our exacting standards:
- Very fine particle size (either 1.8µm or 2.3µm) for good dispersion and surface finish
- Stability at very high temperatures for high temperature processing of polymers such as nylon
- Consistent round particle shape for improved powder flow
- Consistent bulk density and particle size distribution
- Tight production specifications
A supplier you can trust
The borates used in our products are extracted and purified at the source, our mine in Boron, California. Firebrake ZB is then combined with pure zinc oxide at our Wilmington operations before being shipped to distributors and customers around the globe.
U.S. Borax pioneered the use of zinc borate as a fire retardant. Our leading industry experts offer technical advice, troubleshooting, and formulation support, including:
- Applications and uses of our products
- Which polymer to use for an application
- Polymer processing temperatures
- Working with halogenated or halogen-free fire retardancy systems
- Meeting fire safety standards
- Smoke restrictions
In addition, our product stewardship team can provide support and guidance on regional and global regulatory issues.
If you're a polymer manufacturer, contact us to discuss what product might be right for your process.
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