Smoke suppressants

Alumina trihydtate is also used as a secondary flame retardant and smoke suppressant for flexible poly(vinyl chloride) and polyolefin formulations in which antimony and a halogen ate used. The addition of minor amounts of either zinc borate or phosphoms results in the formation of glasses which insulate the unbumed polymer from the flame (21). 

Molybdenum Oxides. Molybdenum was one of the first elements used to retard the flames of ceUulosics (2). Mote recently it has been used to impart flame resistance and smoke suppression to plastics (26). Molybdic oxide, ammonium octamolybdate, and zinc molybdate ate the most widely used molybdenum flame retardants. Properties ate given in Table 5. These materials ate recommended almost exclusively for poly(vinyl chloride), its alloys, and unsaturated polyesters (qv). 

Molybdenum is also a smoke suppressant for poly(vinyl chloride). It promotes the formation of cis- rather than the trans-polymeric decomposition products which ate the precursors for smoke. The sources for molybdates ate Climax Performance Material Cotp. and Sherwin WiUiams. 

F. W. Moor, Molybdenum Compounds as Smoke Suppressants for Polyvinyl Chloride, Society of Plastics Engineers (SPE ANTEC), Montreal, Canada, 1977. 

Smoke Suppression of Rigid HinylEsingMolybdenum Compounds, Technical Bulletin No. 2 Climax Performance Materials Corp. 

TrialkylPhosphates. Triethyl phosphate [78-40-0] C H O P, is a colorless Hquid boiling at 209—218°C containing 17 wt % phosphoms. It may be manufactured from diethyl ether and phosphoms pentoxide via a metaphosphate intermediate (63,64). Triethyl phosphate has been used commercially as an additive for polyester laminates and in ceHulosics. In polyester resins, it functions as a viscosity depressant as weH as a flame retardant. The viscosity depressant effect of triethyl phosphate in polyester resins permits high loadings of alumina trihydrate, a fire-retardant smoke-suppressant filler (65,66). 

Uses. The principal use of magnesium hydroxide is in the pulp (qv) and paper (qv) industries (52). The main captive use is in the production of magnesium oxide, chloride, and sulfate. Other uses include ceramics, chemicals, pharmaceuticals, plastics, flame retardants/smoke suppressants, and the expanding environmental markets for wastewater treatment and SO removal from waste gases (87). 

Numerous variations in composition, appHcation method and surface treatment, and properties of Mg(OH)2-containing flame-retardant fillers are disclosed in the patent Hterature (92—95). Smoke-suppressant foams incorporating Mg(OH)2 are useful as roof insulation slabs (96). Mg(OH)2 is contained... 

Certain anhydrous stannates are effective as smoke suppressants in glass-reinforced polyester, especially Na2Sn(OH)g [12058-66-1] and ZnSnO ... 

Other flame retardants and/or smoke suppressants can also be used such as magnesium hydroxide, magnesium carbonate, magnesium-zinc complexes and some tin-zinc compositions. Zinc oxide is a common ingredient in many rubber base formulations used as part of the curing system. At the same time, the action of zinc oxide is similar to that of antimony trioxide, but less effective. 

The flare tip assembly shall be furnished complete with smoke suppression system, pilot and igniter assemblies, windshield, and flame retention assembly. 

The scope of supply includes all the required equipment, piping and instrumentation for proper flaring of gaseous effluents with smoke suppression system. The scope of supply shall include at least ... 

Flare smoke suppression system consisting of an air duct mixing section, air nozzle ring header and associated duct work from ground level to fire tip. 

NOTE Where smoke suppression is required (e.g., in a boiler fired on poor-quality heavy fuel oil) and a typical liquid combustion improver product is employed, to achieve a 35% reduction in unbumed particles may require the addition of 2/3 pint of additive per 2,500 gallons of fuel (approximately 0.33 liters per 10m3). Doubling the smoke particle reduction to 65%, however, may require triple the feed rate of the additive. 

Friction agents Odour modifiers Plasticisers Smoke suppressants... 

Flame retardants - Fire retardants - Smoulder retardants -Smoke-suppressants Flexibilisers Flow improvers... 

Finely divided magnesium or aluminium hydroxides (or a 3 1 combination) are currently the best smoke suppressants. They also neutralise the acidic vapours produced from halogen-containing flame inhibiters. The more finely divide they are the more efficient they become. 

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 A SMOKE SUPPRESSANT. Antimony oxide performs well as a flame retardant in flexible PVC, however, as a gas phase flame retardant, its use can drastically increase the smoke production during PVC combustion as illustrated in Fig. 8. The zinc borate,... 

Fig. 11 illustrates the smoke suppression effect of the zinc borate when used in conjunction with ATH in a halogen-free ethylene-vinyl acetate (EVA) system. Sumitomo Electric, in a... 

More recently, General Electric reported the use of the zinc borate as a smoke suppressant in a halogen-free si 1 icone-polyetherimide copolymer (8). 

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

In halogen-free polymers, the zinc borate in combination with ATH at high loadings can also function as a flame retardant and smoke suppressant by releasing water and forming a porous ceramic residue, which acts as a thermal insulator. 

At the present time, inorganic tin compounds find a relatively small use in natural polymers, particularly as flame-resist treatments for woollen rugs and sheepskins (8,9). Although certain other metal derivatives have received more attention, there has been much interest recently in the potential use of tin chemicals as flame retardants and smoke suppressants for synthetic polymers (10). 

Hence, it is apparent that certain inorganic tin compounds are very effective flame retardants and smoke suppressants for halogenated polymer formulations. Since these additives are generally non-toxic, their potential use as partial or total replacements for existing commercial flame retardants, such as antimony trioxide, is thought to merit serious consideration. 

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