Boron Flame Retardant

Boron flame retardants (FRs) are increasingly attracting attention in the field of flame retardant due to their advantages such as high efficiency flame retardant, low toxicity and environmental protection, and effective smoke suppression. Alfa Chemistry offers a range of high-quality boron flame retardants for realizing your innovative flame retardant material ideas.

Classification

• Inorganic boron FRs

Inorganic boron FRs are mainly boric acid, borax and borate. Among them, inorganic borate series FRs include barium metaborate, ammonium fluoroborate, metaboric acid, sodium, ammonium pentaborate, ammonium metaborate, zinc borate, etc.

• Organic boron FRs

Organic boron FRs mainly include tris(2,3-dibromo)propyl borate, polyborosiloxane and so on.

• Multi-component composite boron FRs

Organoboron FRs are used in combination with other FRs to improve their hydrolysis resistance. There is a synergistic flame retardant effect between boron and phosphorus, nitrogen, silicon and other elements.

Advantages

• Wide range of raw material sources (boric acid, borax, etc.)
• Efficient flame retardant
• Low toxicity and environmental protection
• Effective smoke suppression
• Good stability

Flame Retardant Mechanism

The flame retardant effect of boron-based FRs can be achieved from the following aspects:

• The FR melts when it burns, absorbing some of the heat.
• The FR coats the polymer surface to isolate the combustible from contact with oxygen.
• FRs release bound water at high temperatures, which evaporates and cools the material.
• The thermal decomposition pathway of combustibles is changed, and the generation of combustible gases is reduced.
• If used in combination with nitrogen-containing and halogen flame retardants, the generated flame-retardant gases NH₃ and HX can dilute the concentration of oxygen.

Applications

Zinc borate is one of the most widely used inorganic boron FR. Zinc borate also has various functions such as flame retardant, smoke suppression, char formation, smoldering suppression and droplet prevention, etc. It is widely used as a flame retardant in fiber fabrics, polyamide, nylon, and polyurethane.

Besides, Zinc borate is often used in conjunction with brominated flame retardants, Al(OH)₃, Mg(OH)₂ and intumescent flame retardants to replace toxic SB₂O₃.

Research Information

Boron and phosphorus synergistic flame retardant

Some studies have pointed out that boron (B) and phosphorus (P) have a synergistic flame retardant effect, and the flame retardant mechanism of the synergistic system has been explored. The compositional synergistic effect of B/P compounds in epoxy resins (EP) was explored by Shuo Tang et al. In this work, all three B/P compound systems inhibited heat release, increased residue yield and exerted smoke suppression effects. Among them, the B₂O₃ /TAD system has the best flame retardant effect on EP composites. Because B₂O₃ can interact with the epoxy resin matrix, increase the amount of carbonization and the quality of carbonization, and produce obvious condensed phase flame retardant effect. [2]

B₂O₃/TAD bi-phase synergistic flame retardant mechanism [1]

Reference

1. Shuo Tang, et al. (2018), "Synergistic flame-retardant effect and mechanisms of boron/phosphorus compounds on epoxy resins," Polym Adv Technol. 29(1), 641-648.