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Zinc Borate

Zinc Borate

Zinc Borate is a Boron based flame retardant compatible with many polymeric matrices. It is effective both in the solid phase and in the gas phase and its strong smoke suppressing action, helps to improve time of rescue in case of fire.

Zinc Borate is a multifunctional flame retardant:

 

  • promotes the formation of a protective vitreous layer and of a strong char layer, which reduces the formation of toxic and irritant smoke during the fire
  • It looses its water of hydration at temperatures above 290°C, cooling the front of the flames and subtracting energy to the fire
  • It acts as a synergist in conjunction with halogenated compounds, so that lower loadings of halogenated flame retardant additives are needed
  • It shows a strong synergic effect with antimony trioxide; in presence of alumina trihydrate (ATH) the synergic effect is enhanced
  • It improves resistance against electrical degradation: high anti-arcing and anti-tracking indexes
  • It is an afterglow suppressant.

 

Zinc borate is an inorganic compound, a borate of zinc. It is a white crystalline or amorphous powder insoluble in water. Its toxicity is low. Its melting point is 980 °C.

Several variants of zinc borate exist, differing by the zinc/boron ratio and the water content:

Zinc borate Firebrake ZB (2ZnO·3 B2O3·3.5H2O), CAS number 138265-88-0

Zinc borate Firebrake 500 (2ZnO·3 B2O3), CAS number 138265-88-0

Zinc borate Firebrake 415 (4ZnO·B2O3·H2O), CAS number 149749-62-2

ZB-467 (4ZnO·6B2O3·7H2O), CAS number 1332-07-6

ZB-223 (2ZnO·2B2O3·3H2O), CAS number 1332-07-6

The hydrated variants lose water between 290–415 °C.

  • Zinc borate is primarily used as a flame retardant in plastics and cellulose fibers, paper, rubbers and textiles. It is also used in paints, adhesives, and pigments. As a flame retardant, it can replace antimony trioxide as a synergist in both halogen-based and halogen-free systems. It is an anti-dripping and char-promoting agent, and suppresses the afterglow. In electrical insulator plastics it suppresses arcing and tracking.
  • In halogen-containing systems, zinc borate is used together with antimony trioxide and alumina trihydrate. It catalyzes formation of char and creates a protective layer of glass. Zinc catalyzes the release of halogens by forming zinc halides and zinc oxyhalides.
  • In halogen-free system, zinc borate can be used together with alumina trihydrate, magnesium hydroxide, red phosphorus, or ammonium polyphosphate. During burning the plastics, a porous borate ceramics is formed that protects the underlying layers. In presence of silica, borosilicate glass can be formed at plastic burning temperatures.
  • Zinc borate is used in polyvinyl chloride, polyolefins, polyamides, epoxy resins, polyesters, thermoplastic elastomers, rubbers, etc. It is also used in some intumescent systems.
  • Zinc borate has synergistic effect with zinc phosphate or barium borate as a corrosion inhibitor pigment.
  • Zinc borate acts as a broad-spectrum fungicide in plastics and wood products.
  • Zinc borate can be used as a flux in some ceramics. In electrical insulators it improves the ceramics properties.
  • Nanopowder zinc borate can be used for the applications above, and also for improving the frictional properties of lubricating oils.



 US Borax

Firebrake® 415

Zinc borate. Used as a flame retardant and smoke suppressant in coatings. Offers high dehydration onset temperature. Suits for systems requiring very high processing temperatures. Gives compatibility with nylon and flexible PVC.

Firebrake® 500

Dehydrated zinc borate. Used as a flame retardant and smoke suppressant in coatings. Contains no water of hydration. Offers very significant beneficial effect on rate of heat release. Suits for systems requiring very high processing temperatures....

Firebrake® ZB

Multifunctional zinc borate. Used as a flame retardant, smoke and afterglow suppressant, and anti-arcing agent in coatings. Suits for systems requiring high processing temperatures. Offers retention of considerable translucency. Allows use of low...

Firebrake® ZB-Fine

Multifunctional zinc borate. Used as a flame retardant, smoke and afterglow suppressant, and anti-arcing agent in coatings. Suits for systems requiring high processing temperatures. Offers retention of considerable translucency. Allows use of low...

Firebrake® ZB-XF

Multifunctional zinc borate. Used as a flame retardant, smoke and afterglow suppressant, and anti-arcing agent in coatings. Suits for systems requiring high processing temperatures. Offers retention of considerable translucency. Allows use of low...

 

 

CHEMTURA

ZB-467

Zinc borate. Acts as a flame retardant/smoke suppressant in cellulosics and textiles coating applications. Possesses compatibility with polyamides, PVC, polyethylene, polypropylene, epoxy, polyesters, elastomers, rubber, polyurethanes, cellulosic and...

 

Fyrebloc® 7DB-201

Flame retardant / Fire retardant >> Antimony oxide

Flame retardant / Fire retardant >> Boron based

Blend of decabromodiphenyl oxide and antimony trioxide. Used as a flame retardant in epoxies and polyesters coatings. Provides improved efficiency and good heat stability. Possesses compatibility thermoplastics such as polyethylene, polypropylene,...

 

Fyrebloc® 7DB-301

Flame retardant / Fire retardant >> Antimony oxide

Flame retardant / Fire retardant >> Boron based

Blend of decabromodiphenyl oxide and antimony trioxide. Used as a flame retardant in epoxies and polyesters coatings. Provides improved efficiency and good heat stability. Possesses compatibility with thermoplastics such as polyethylene,...

 

Fyrebloc® 7DB-401

Flame retardant / Fire retardant >> Antimony oxide

Flame retardant / Fire retardant >> Boron based

Blend of decabromodiphenyl oxide and antimony trioxide. Used as a flame retardant in epoxies and polyesters coatings. Provides improved efficiency and good heat stability. Possesses compatibility with thermoplastics such as polyethylene,...

 

ZB-112R

Flame retardant / Fire retardant >> Boron based

Zinc borate. Used as a flame retardant/smoke suppressant in cellulosics and textiles coating applications. Possesses compatibility with elastomers, rubber and polyurethane, and very little pigmenting power. Can be used as an afterglow suppressant and...

 

ZB-237

Flame retardant / Fire retardant >> Boron based

Zinc borate. Used as a flame retardant/smoke suppressant in coatings. Possesses compatibility with polyurethanes, thermoset resins and cellulosic products, very little pigmenting power and low temperature of activation. Can be used as an afterglow...