Polymer flame retardant for any temperature

The U.S. Borax Firebrake® family of products can be used in a multitude of formulations for fire retardancy in polymers, plastics, and rubber compounds.

Firebrake ZB is a unique zinc borate that combines the best of zinc and boron oxides with water release. Because Firebrake ZB releases its water of hydration at temperatures exceeding 554°F (290°C), it can be used in systems that require high processing temperatures. Firebrake ZB has a refractive index similar to that of most polymer systems, so it retains considerable translucency and enables the use of low pigment loading.

Firebrake 500 is an anhydrous zinc borate for multi-functional fire-retardant applications in a variety of polymers. Because it contains no water of hydration, it is stable up to 1112°F (600°C) and can be used in polymer systems that require very high processing temperatures.

Firebrake ZB

2ZnO·3B2O3 ·3.5H2O
Zinc Borate

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› Specification sheets

Product data sheet

Firebrake 500

2ZnO ·3B2O3
Anhydrous Zinc Borate

› Safety data sheets
› Specification sheets

Product data sheet

Made In

USA

What can Firebrake products do for you?

Both Firebrake products can be fed to extruders, calenders, or injection molding equipment, much like other solid polymer additives.

Firebrake ZB provides fire retardant protection for polymers

Firebrake ZB is used as a flame retardant, char promoter, afterglow and smoke suppressant, and anti-arc agent in polymer systems, including:
  • Polyvinyl chloride
  • Nylon
  • Epoxy
  • Polyethylene
  • Polypropylene
  • Polyesters
  • Elastomers 

Depending on the base polymer that you use and the fire protection standards you must meet, you can use Firebrake ZB to partially or completely replace other fire-retardant additives such as antimony oxide. (In some systems, Firebrake ZB displays synergism with antimony oxide.)

For situations that demand maximum fire-test performance as well as film forming and adhesion, Firebrake ZB is available in fine and extra-fine formulations. The extra-fine grade has no particles greater than 12 microns (as determined by laser diffraction) and is suitable for more critical flame retardant applications.

Firebrake products are used in a variety of fire retardant applications.
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Firebrake 500 protects polymers in very-high-temperature processes

Firebrake 500 is an anhydrous form of Firebrake ZB that is specially designed for applications in which no water evolution is permitted. You can use Firebrake 500 as a flame retardant, char promoter, and smoke suppressant in a variety of polymers, including:
  • High temperature polyamides (PPA) and polyamide 6.6
  • Polyetherketones
  • Polysulfones
  • Fluoropolymers
  • Polyesters 
Firebrake 500 has a significant beneficial effect on the rate of heat release, a quality that is of special interest in aircraft applications. It can also function as a corrosion inhibitor in polymer processing.
 

Applications

Fire Retardancy


U.S. Borax products are used in a variety of fire retardant applications, including polymer-based applications, cellulose protection, lumber, and plywood.
 

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Polymers and Coatings


Polymers can ignite and burn easily which is why flame retardant additives are often required to meet safety standards. One of the many commercial applications of borates is fire retardancy.
 

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Chemical and Physical Properties

Refractive Index: 1.58

Median particle size (laser diffraction):
Firebrake ZB Fine: ≤ 2.5 microns
Firebrake ZB-XF: ≤ 2.2 microns

Molecular weight: 434.67

Specific gravity: 2.77

Appearance: White, crystal-like powder

Solubility: Less than 0.28% in water at room temperature

Stability: Thermally stable up to 554°F (290°C); can be hydrolyzed by strong acids and bases


Chemical Composition (Theoretical)

Boric oxide, B2O3: 48.05%

Zinc oxide, ZnO: 37.44%

Water of crystallization, H2O: 14.51%

Anhydrous equivalent: 85.49%

Containers: Products may be available in bulk, IBCs, or small bags
 

Additional assistance

Have questions about how Firebrake ZB is working in your formulations? Contact our fire retardancy and polymer technical expert for help.

Chemical and Physical Properties

Refractive Index: 1.58

Median Particle Size: ≤12 microns (laser diffraction)

Weight Loss (TGA): 1.5% maximum to 400°C

Stability: Thermally stable to >600°C; can gradually absorb surface moisture

Molecular weight: 371.62

Specific gravity: 2.6

Appearance: White, crystal-like powder

Stability: The product is chemically stable and shows little tendency to cake.


Chemical Composition (Theoretical)

Boric oxide, B2O3: 56.20%

Zinc oxide, ZnO: 43.80%

Containers: Products may be available in bulk, IBCs, or small bags

Store Firebrake 500 in a sealed container because of its tendency to gradually pick up surface moisture in high-humidity environments. This surface moisture is easily removed by heating at about 200°C.

Additional Assistance

Have questions about how Firebrake 500 is working in your formulations? Contact our fire retardancy and polymer technical expert for help.

Firebrake 500 Product Details


 
SPECIFICATIONS SHEET
Granular

 

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We’re here to help with your boron needs.

Contact sales


Our regional sales teams are ready to help with your purchase

Learn More

Get technical support

 

Your resource for borate-related technical and laboratory services across every industry

Learn More

Request a sample


Get small quantities of our products to ensure you have what you need for your formulation or process

Learn More

Firebrake in Action

Zinc Borates for Fire Retardancy, Safety, and Performance
Polymer producers face a range of challenges as they strive to find a balance of safety, sustainability, and quality in their products. Firebrake produ... Learn More
Firebrake ZB in Coatings for Fire Retardant Paint
Firebrake ZB provides multifunctional benefits in a wide variety of solvent-based and aqueous fire-retardant coatings, including epoxies, vinyl chlorid... Learn More
Building Resilience: Borates for Treated Lumber and Engineered Wood Products
In a year of disruption, the lumber industry has been on a roller coaster of demand fluctuations. Adaptations from producers—and U.S. Borax—have h... Learn More

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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