Flame retardant synergists

Poly(vinyl chloride). PVC is a hard, brittle polymer that is self-extinguishing. In order to make PVC useful and more pHable, plasticizers (qv) are added. More often than not the plasticizers are flammable and make the formulation less flame resistant. Flammability increases as the plasticizer is increased and the relative amount of chlorine decreased, as shown in Table 7. The flame resistance of the poly(vinyl chloride) can be increased by the addition of an inorganic flame-retardant synergist. 

Of the tin additives studied, the anhydrous and hydrated zinc stannates, ZnSnO and ZnSn(OH), respectively, are considerably more effective flame-retardant synergists with the bromine present in the plastic than 8-stannic acid (Figure 1). In line with this observation, oxidic tin-zinc systems have previously been found to exhibit superior flame-retardant properties to tin oxides alone (19-22). In addition, ZnSnO, gives higher values of 01 than Sb20, incorporation levels studied, and, in fact, the 1% ZnSnO - containing plastics outperform samples containing 2% Sb O,. 

It is of interest to note that the polymer containing ZnSn(OH) does not burn in air even at 250°C and, accordingly, this composition has a temperature index of at least 50°C above that of the rubber containing ATH alone. The 01 and high temperature 01 data therefore provide substantial evidence as to the benefit of using ZnSn(OH) as a flame-retardant synergist with alumina trihydrate filler. 

Zinc hydroxystannate and zinc stannate are very effective flame-retardant synergists when incorporated at levels of 1-10% into... 

Certain inorganic tin compounds are effective flame-retardant synergists when incorporated at a 2.5% level into a 50% ATH-filled ethylene-acrylic rubber composition. Tin-containing elastomer formulations retain their flame-retardant superiority at environmental temperatures up to 250°C, and samples containing 2.5% ZnSn(0H)g do not sustain combustion in air at this temperature. 

Antimony oxide is known as a flame retardant synergist when used in combination with halogen compounds. Volatile antimony oxyhalide (SbOX) and/or antimony trihalide (SbX3) are formed in the condensed phase and transport the halogen into the gas phase (3). It has been suggested that antimony is also a highly active radical trap (4). 

Costa, L. Luda, M. P Trossarelli, L. Mechanism of condensed phase action in flame retardants. Synergistic systems based on halogen-metal compounds, Polymer Degradation and Stability, 2000, 68(1), 67-74. 

S. Nie, Y. Hu, L. Song, S. He, and D. Yang, Study on a novel and efficient flame retardant synergist nanoporous nickel phosphate VSB-1 with intumescent flame retardants in polypropylene, Polym. Adv. Technol., 2008, 19 489 195. 

Other flame-retardants selected as priority chemicals for the EU Risk Assessment process included tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), tris(2-chloroethyl) phosphate (TCEP), tris (2-chloropropyl) phosphate (TCPP), tris(2-chloro-l-(chloromethyl)ethyl) phosphate (TDCP), and 2,2-bis(chloromethyl) trimethylene bis (bis(2-chloroethyl)phosphate) (V6). The flame-retardant synergist, antimony trioxide (Sb ), was also identified as a priority substance. Table 22.1 contains information on the EU Risk Assessments on the nine flame-retardants and one synergist. 

Flame Retardance-Highly effective organic flame retardant -Synergistic with all inorganic flame retardants... 

PSE/PC or PET, ZnBOj and PTFE flame-retardant, synergistic properties Jack et al., 1993... 

Chem. Descrip. Antimony trioxide CAS 1309-64-4 EINECS/ELINCS 215-175-0 Uses Flame-retardant synergist tor plastics, rubber, paper and paint polymerization catalyst tor PET resins and libers also for electronics, glass, ceramics, petrol, retining, and chem. mtg. 

Some fillers perform valuable specialist functions and some are discussed in other sections of this report. One example is aluminium trihydroxide (ATH), discussed under the heading of Flame Retardants and Smoke Suppressants, rather than Fillers. Carbon black has several roles, improving polymer conductivity, electrostatic dissipation and UV stabihsation. Antimony trioxide is a flame retardant synergist. 

Great Lakes has joined with Laurel Industries, part of Occidental Petroleum (OxyChem) to form a 50 50 JV called GLCC Lamel LLC. The JV was intended to compete with cheap Chinese antimony imports by producing and marketing antimony-based flame retardants, synergists, and catalysts. Great Lakes has the responsibility for sales, customer service, techiucal support, credit and logistics. 

Stannates. Zinc stannate [12036-37-2], Alcan s FLAMTARD S, and zinc hydroxystannate [12027-96-2], FLAMTARD HS, are both white water-insoluble powders useful as smoke suppressants in PVC. They can partly replace antimony oxide as flame-retardant synergists in halogen-containing flame-retardant formulations, with reduced smoke (16,17). 

By means of compounding, tailor-made engineering plastics parts are manufactured to satisfy every conceivable application. The warping problem, which existed in the past for the production of large area parts, e.g. for car body parts and bumpers, can be overcome by selected reinforcement/filler systems. Simultaneously the heat distortion temperature could be raised from about 150 °C for pure PBT homopolymer to approximately 210 °C for reinforced polymer. Self-extinguishing behavior was imparted by incorporation of flame retardant synergistic systems. Further, in the last thirty years, many commercial products have been developed by blending PBT with other polymers in the melt. Moreover, a variety of additives, fillers or reinforcements, which have been mentioned previously in this Chapter, may be added to the PBT blends. 

Fillers may promote char magnesium hydroxide, zinc borate, antimony oxides require high loadings and can degrade mechanical and other properties. Toxicity of antimony-based retardants is a concern. Can be used with other flame retardants synergistically. 

Touval, 1. (1996) Antimony flame retarder synergists. Flame Retardants 101, Baltimore, 24-27/3/1996, Fire Retardant Chemicals Association. 

Blunden, S.J., Cusack, P.A. and Hill, R. (1985) Fire retardants in The Industrial Uses of Tin Chemicals, The Royal Society of Chemistry, London, pp. 172-209. Touval, 1. (1972) The use of stannic oxide hydrate as a flame retardant synergist. Journal of Fire and Flammability, 3,130-43. 

In order to improve the flame retarding action of these Fyarestor additives, antimony trioxide can be enqployed as a flame retarding synergist in these applications which tolerate the use of a powdered additive. The use of this metal oxide will reduce the flame retarding cost. Also, the Fyarestor products can be emulsified for use in water-based systems. Typical Properties ... 

LSFR additive, a proprietary flame retardant synergist, meets the increasing demand for PVC and other polymer products that are not only fire resistant, but smoke resistant as well. Further, LSFR enhances the physical properties of polymers in six additional ways, making it one of the most cost-effective flame retardant additives available. In addition, it offers low specific gravity euid bulk density, and no compromise to your compound s physical integrity. 

Charmax Anwoniun Octanolybdate is an ultrafine whita to off-white powder of exceptionally high purity used as a flame retardant synergist and smoke suppressant in polymers. 

Flame Retardant Synergist-Antimony oxide in combination with a halogen source constitutes an extremely effective flame retardant for use in broad range of polyaiers. 

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