Additives antimony trioxide

In spite of this maturing of the subject, it is clear that there are still many aspects in which disagreements persist about the mechanisms involved, and which as a result are unclear or misunderstood among users, and perhaps even more importantly, among potential users. These aspects range from the mechanism of action of the important additive antimony trioxide to the behaviour of molybdenum disulphide in the presence of liquids, and the critical importance of consolidation of molybdenum disulphide films. 

Carcinogen list (monomer additives) antimony trioxide, cadmium and cadmium ... 

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 ... 

Sodium antimonate contains less antimony than either antimony trioxide or pentoxide and is thus less effective. However, its unique pH and low refractive index makes the antimonate the most desirable synergist for polymers that hydrolyze when processed with acidic additives or in polymers for which deep color tones are specified. Sodium antimonate costs approximately 3.30—4.40/kg and can be obtained from either Elf Atochem NA under the Thermoguard name or from Anzon Inc. as a Timinox product. 

Mixed Metal Antimony Synergists Worldwide scarcities of antimony have prompted manufacturers to develop synergists that contain less antimony. Other metals have been found to work in concert with antimony to form a synergist that is as effective as antimony alone. Thermoguard CPA from Elf Atochem NA, which contains zinc in addition to antimony, can be used instead of antimony oxide in flexible poly(vinyl chloride) (PVC) as well as some polyolefin appHcations. The Oncor and AZ products which contain siUcon, zinc, and phosphoms from Anzon Inc. can be used in a similar manner. The mixed metal synergists are 10 to 20% less expensive than antimony trioxide. 

Antimony Oxide. The effect of antimony trioxide on the oxygen index of flexible poly(vinyl chloride) containing from 20 to 50 parts of plasticizer is shown in Figure 2. The flame resistance as measured by the oxygen index increases with the addition of antimony oxide until the oxygen index appears to reach a maximum at about 8 parts of Sb202. Further addition of antimony oxide does not have any increased beneficial effect. 

Flame Retardants. Flame retardants are added to nylon to eliminate burning drips and to obtain short self-extinguishing times. Halogenated organics, together with catalysts such as antimony trioxide, are commonly used to give free-radical suppression in the vapor phase, thus inhibiting the combustion process. Some common additives are decabromodiphenyl oxide, brominated polystyrene, and chlorinated... 

Antimony trioxide is insoluble in organic solvents and only very slightly soluble in water. The compound does form a number of hydrates of indefinite composition which are related to the hypothetical antimonic(III) acid (antimonous acid). In acidic solution antimony trioxide dissolves to form a complex series of polyantimonic(III) acids freshly precipitated antimony trioxide dissolves in strongly basic solutions with the formation of the antimonate ion [29872-00-2] Sb(OH) , as well as more complex species. Addition of suitable metal ions to these solutions permits formation of salts. Other derivatives are made by heating antimony trioxide with appropriate metal oxides or carbonates. 

A key property associated with chlorinated paraffins, particularly the high chlorine grades, is nonflammability, which has led to their use as fire-retardant additives and plasticizers in a wide range of polymeric materials. The fire-retardant properties are considerably enhanced by the inclusion of antimony trioxide. 

Chlorinated paraffins are versatile materials and are used in widely differing appHcations. As cost-effective plasticizers, they are employed in plastics particularly PVC, mbbers, surface coatings, adhesives, and sealants. Where required they impart the additional features of fire retardance, and chemical and water resistance. In conjunction with antimony trioxide, they constitute one of the most cost-effective fire-retardant systems for polymeric materials, textiles, surface coatings, and paper products. Chlorinated paraffins are also employed as components in fat Hquors used in the leather industry, as extreme pressure additives in metal-working lubricants, and as solvents in carbonless copying paper. 

Antimony trioxide reacts with chlorine, either in the rubber or present due to the addition of chlorinated waxes, to give gases which function by reducing the oxygen supply. The reaction produces dense white fumes that exclude air and extinguish flames. 

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. 

Bromine is often preferred as a FR source and, considering that most organo-bromine compounds are only 40-70 wt% bromine and that antimony trioxide is used in blends, FR-PBT blends may contain from 10 to 25 wt% FR additives. This high level of additives will have an effect on the melt processability, density and mechanical properties of the blend. 

Addition of fillers such as alumina trihydrate, antimony trioxide, molybdenum oxide [315], zinc borate and zinc borate complex [316] leads to increase in TS but decrease in elongation and NG migration/absorption. Addition of inorganic fillers also leads to increase in flame retardance. 

Many metal salts are well-known primary skin irritants. These substances include antimony trioxide, arsenic trioxide, chromium and alkaline chromates, cobalt sulfate, nickel sulfate, mercury chloride, and zinc chloride. In addition to the above industrial chemicals, several solvents are known to act as primary skin irritants among workers, such as, carbon tetrachloride (CCI4), chloroform, ethylene dichloride, epichlorohydrin, ethylene chlorohydrin, perchloroethylene, and trichloroethylene, in addition to cool tar solvents such as naphtha, toluene, and xylene. 

To improve the fire retardancy of polypropylene, beyond the UL 94 V-2 level, it is necessary to use blends of aromatic bromine fire retardants with antimony trioxide as a synergist. The usual loading is between 35% and 40% fire retardant however, the additional cost may prohibit commercialization. Moreover, the presence of aromatic bromine increases the photooxidation of polypropylene67 69 inactivating hindered amines. To reduce the cost without losing in efficacy the combination of brominated flame-retardant/antimony trioxide system with magnesium hydroxide... 

The combination of melamine with hydrated mineral fillers can improve the fire retardancy behavior of PP, eliminating at the same time the afterglow phenomenon associated with these fillers used in isolation.70 Similarly in EVA copolymer, antimony trioxide used in combination with metal hydroxides has been reported to reduce incandescence.56 Chlorinated and brominated flame retardants are sometimes used in combination with metal hydroxides to provide a balance of enhanced fire-retardant efficiency, lower smoke evolution, and lower overall filler levels. For example, in polyolefin wire and cable formulations, magnesium hydroxide in combination with chlorinated additives was reported to show synergism and reduced smoke emission.71... 

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). 

The CPSC staff performed quantitative risk assessments on various flame-retardants for both upholstered residential furniture fabrics and foam.89 CPSC addresses chemical hazards under the Federal Hazardous Substances Act (FHSA), which is risk based. For fabrics, five flame-retardants were evaluated, that include antimony trioxide, deca-BDE, HBCD, phosphonic acid, (3- [hydroxymethyl]amino)-3-oxopropyl)-, dimethyl ester (PA), and tetrakis (hydroxymethyl) phosphonium chloride (THPC). These flame-retardants were selected for study because they are used to comply with the U.K. upholstered furniture flammability standard (except THPC) and fabric samples were available for testing. The staff concluded in 2006 that deca-BDE, HBCD, and PA would not present a hazard to consumers and that additional data would be needed to assess antimony trioxide and THPC. 

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