Afterglow suppression

Ba(B02)2 H2O, used in flame retardant plastic formulations as a synergist for phosphoms or halogen compounds and as a partial or complete replacement for antimony oxide (see Flame RETARDANTS), is excellent as an afterglow suppressant. The low refractive index of results in greater... 

Zinc Borate as a Flame Retardant, Smoke Suppressant, and Afterglow Suppressant in Polymers... 

Zinc Borate (2Zn0-3B203-3.5H20) is a unique multifuntional fire retardant. It can function as a flame retardant, smoke suppressant, afterglow suppressant, as well as an anti-tracking agent in polymers. It has been used extnesively as a fire retardant in PVC, polyolefin, nylon, polyester, epoxy, acrylic, urethane, rubbers, etc. 

A Multifunctional Smoke Suppressant, Flame Retardant, and Afterglow Suppressant. 

AS AN AFTERGLOW SUPPRESSANT. Due to its unique glass-forming ability (i.e., from the B203 moiety), the zinc borate can also function as an afterglow suppressant as illustrated in Table... 

In halogen-containing polymers, the multifunctional zinc borate can function as a flame retardant, smoke suppressant, and afterglow suppressant. 

Polyolefins When used in conjunction with a halogen-based flame retardant, this zinc borate can partially replace antimony oxide (30%-40%) and still maintain the same fire test performance. In addition, it can improve aged elongation properties, increase char formation, and decrease smoke generation. The B203 moiety in zinc borate can also provide afterglow suppression (Table 9.6). 

Melamine diborate (MB), known in the fire-retardant trade as melamine borate, is a white powder, which can be prepared readily from melamine and boric acid. It is partly soluble in water and acts as an afterglow suppressant and a char promoter in cellulosic materials. Budenheim Iberica79 claims that, in a 1 1 combination with APP, MB (10%-15%) can be used for phenolic bound nonwoven cotton fibers. In general, melamine borate can be used as a char promoter in intumescent systems for various polymers including polyolefins or elastomers. However, its low dehydration temperature (about 130°C) limits its application in thermoplastics that are processed at above 130°C. Melamine borate is also reported to suppress afterglow combustion in flame-proofing textiles with APP or monoammonium phosphate to meet the German DIN 53,459 and Nordtest NT-Fire 002.80... 

Another school of thought believes that the efficacy of boric oxide in afterglow suppression is related to its high ionization energy/or electron affinity active sites for oxygen adsorption on the char surface may be deactivated by boric oxide via electron transfer. It was reported that boric oxide increases the oxidation temperature of crystalline carbon from 700°C to 800°C.109... 

Zinc borates are predominately a condensed phase fire retardant. In a halogenated system such as flexible PVC, it is known to markedly increase the amount of char formed during polymer combustion whereas the addition of antimony trioxide, a vapor-phase flame retardant, has little effect on char formation. Analyses of the char show that about 80%-95% of the antimony is volatilized, whereas the majority of the boron and zinc from Firebrake ZB remains in the char (80% and 60%, respectively).48-56 The fact that the majority of the boron remains in the condensed phase is in agreement with the fact that boric oxide is a good afterglow suppressant. The mode of action can be summarized in the following equation (not balanced). 

Boron-based fire retardants have a wide spectrum of applications. They are multifunctional fire retardants. They can function as flame retardants, smoke suppressants, afterglow suppressants, and anti-tracking agents. 

Shen, K.K. and Griffin T.S. 1990. Zinc borate as a flame retardant, smoke suppressant, and afterglow suppressant in polymers. In Fire and Polymers (ACS Symposium Series, vol. 425), Nelson G.L. (ed.). American Chemical Society, Washington, DC, p. 157. 

A solid afterglow suppressant recommended for use with CALIBAN f/R P-44, P-53, P-66 when required. 

Caliban F/R P-110 White Phosphorus polymer 32% P — — solid Afterglow suppressant in PUR foam... 

The finding that boron remains in the condensed phase is consistent with reports that zinc borate is a good afterglow suppressant [133]. At combustion temperatures, studies of the zinc oxide-boric acid phase diagram [ 134] have established that zinc borate separates into a nearly pure, molten, boric oxide phase and a 1 1 zinc borate (Zn0 <.B203). Both boron and boric oxide are known to be strong inhibitors of the oxidation of carbonaceous materials [135]. 

Ke3Words borates, flame retardant, boric acid, borax, char, boric oxide, smoke suppression, afterglow suppression, dehydration temperature. 

The ZB 400 Series of Charmax Zinc Borates retain their water of hydration at high enough temperatures to process polyamides, polypropylene, and thermoplastic elastomers where they are also used as afterglow suppressants and anti-arcing agents. 

Firebrake zb is used as a flame retardant, smoke and afterglow suppressant, and anti-arcing agent in polymer systems such as polyvinyl chloride, nylon, epoxy, polyethylene, polypropylene, polyesters, thermoplastic elastomers and rubbers. 

In particular in halogen-free systems, there are major advantages with respect to smoke suppression, afterglow suppression, corrosion inhibition, by combining zinc borates with other flame retardants in certain polymers, such as ethylene vinyl acetate, polyfvinyl chloride), poly(amide) (PA). 

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