Flame retardants antimony oxide

Antimony Oxide as a Primary Flame Retardant. Antimony oxide behaves as a condensed-phase flame retardant in cellulosic materials (2). It can be appHed by impregnating a fabric with a soluble antimony salt followed by a second treatment that precipitates antimony oxide in the fibers. When the treated fabric is exposed to a flame, the oxide reacts with the hydroxyl groups of the cellulose (qv) causing them to decompose endothermically. The decomposition products, water and char, cool the flame reactions while slowing the production and volatilization of flammable decomposition products (see Flaa retardants for textiles). 

There is a need for good alternatives for brominated flame retardants. Apart from other disadvantages, the heavy metal antimony is necessary for the production of brominated (or chlorinated) flame retardants. Antimony oxides, Sb205 (used in reactive flame retardants) and Sb203, are used as synergists to increase the efficiency of bromine and chlorine. Bromine and chlorine (together), and antimony oxides are used at a ratio of 1 3 [7]. 

Nyacol Products Inc. manufactures colloidal antimony pent-oxide and blends with halogen compounds for use as flame retardants. Antimony oxide reacts with halogen acids (HCl or HBr) to form volatile compounds that terminate combustion reactions and extinguish the flame. A variety of forms are available for many end uses. 

Flame retardant epoxy Flame retardant (antimony oxide)... 

Flame retardants antimony oxide, halogenated compoimds Flame retardants halogenated compounds... 

Flame retardants antimony oxide, phosphorus compounds, halogenated compounds, antoxidants... 

It is possible to determine components in complex EPs where matrix effects can be severe. For example, zinc (as zinc borate), chlorine (as dechlorane flame retardant), antimony (as oxide) and fibre-glass have been determined in nylon using just one standard. Many users have refined the universal precalibrated programmes for standardless XRF and made them more efficient for matrix correction by using variable correction coefficients. OilQuant offers possibilities for analysing polymers [243]. Software packages usually provide ... 

A typical flame retardant is a mixture of chlorinated alkane (a compatible substance that provides HCl to the flame) and antimony oxide. These have a synergistic effect, forming antimony trichloride in the flame. Hydrogen chloride, formed in the flame, reacts with the high energy hydroxide free radicals formed by polymer decomposition... 

Phosphorus-based flame retardants are usually more suitable for engineering plastics that undergo charring than for commodity polymers. In some plastics, such as PC-ABS or poly(phenylene oxide)-HIPS blends, phosphorus-based flame retardants are more effective then halogenated flame retardants. Antimony trioxide, which is a part of halogen-containing formulations, is a Lewis acid and may destabilize some condensation polymers. Furthermore, the impact properties of engineering polymers may suffer due to the presence of powdery antimony trioxide. 

Acryhc and modacryhc fibers are sold mainly as staple and tow products with small amounts of continuous filament fiber sold in Europe and Japan. Staple lengths may vary from 25 to 150 mm, depending on the end use. Eiber deniers may vary from 1.3 to 17 dtex (1.2 to 15 den) 3.2 dtex (3.0 den) is the standard form. The appearance of acryhcs under microscopical examination may differ from that of modacryhcs in two respects. Eirst, the cross sections (Eig. 1) of acryhcs are generally round, bean-shaped, or dogbone-shaped. The modacryhcs, on the other hand, vary from irregularly round to ribbon-like. The modacryhcs may also contain pigment-like particles of antimony oxide to enhance their flame-retardant properties. 

Ammonium Fluoroborate. Ammonium fluoroborate [13826-83-0] NH BF, is unique in that when it is exposed to a flame, it generates both a halogen and a boron flame retardant (20). Antimony oxide is usually recommended as a co-synergist. 

Molybdenum Oxide. Molybdenum compounds incorporated into flexible PVC not only increase flame resistance, but also decrease smoke evolution. In Table 10 the effect of molybdenum oxide on the oxygen index of a flexible PVC containing 50 parts of a plasticizer is compared with antimony oxide. Antimony oxide is the superior synergist for flame retardancy but has Httle or no effect on smoke evolution. However, combinations of molybdenum oxide and antimony oxide may be used to reduce the total inorganic flame-retardant additive package, and obtain improved flame resistance and reduced smoke. 

Table 10. Effect of Flame Retardancy of Molybdenum Oxide and Antimony Oxide ...

Alumina Trihydrate. Alumina trihydrate is usually used as a secondary flame retardant in flexible PVC because of the high concentration needed to be effective. As a general rule the oxygen index of flexible poly(vinyl chloride) increases 1% for every 10% of alumina trihydrate added. The effect of alumina trihydrate on a flexible poly(vinyl chloride) formulation containing antimony oxide is shown in Figure 5. 

Polymer UL-94 rating at 3.2 mm Flame retardant, wt % Antimony oxide, wt %... 

Cblorina.ted Pa.ra.ffins, The term chlotinated paraffins covers a variety of compositions. The prime variables are molecular weight of the starting paraffin and the chlorine content of the final product. Typical products contain from 12—24 carbons and from 40—70 wt % chlorine. Liquid chlotinated paraffins are used as plasticizers (qv) and flame retardants ia paint (qv) and PVC formulations. The soHd materials are used as additive flame retardants ia a variety of thermoplastics. In this use, they are combiaed with antimony oxide which acts as a synergist. Thermal stabilizers, such as those used ia PVC (see vinyl polymers), must be used to overcome the inherent thermal iastabiUty. 

In polymers such as polystyrene that do not readily undergo charring, phosphoms-based flame retardants tend to be less effective, and such polymers are often flame retarded by antimony—halogen combinations (see Styrene). However, even in such noncharring polymers, phosphoms additives exhibit some activity that suggests at least one other mode of action. Phosphoms compounds may produce a barrier layer of polyphosphoric acid on the burning polymer (4,5). Phosphoms-based flame retardants are more effective in styrenic polymers blended with a char-forming polymer such as polyphenylene oxide or polycarbonate. 

Antagonism between antimony oxide and phosphoms flame retardants has been reported in several polymer systems, and has been explained on the basis of phosphoms interfering with the formation or volatilization of antimony haUdes, perhaps by forming antimony phosphate (12,13). This phenomenon is also not universal, and depends on the relative amounts of antimony and phosphoms. Some useful commercial poly(vinyl chloride) (PVC) formulations have been described for antimony oxide and triaryl phosphates (42). Combinations of antimony oxide, halogen compounds, and phosphates have also been found useful in commercial flexible urethane foams (43). 

A significant advance in flame retardancy was the introduction of binary systems based on the use of halogenated organics and metal salts (6,7). In particular, a 1942 patent (7) described a finish for utilizing chlorinated paraffins and antimony(III) oxide [1309-64-4]. This type of finish was invaluable in World War II, and saw considerable use on outdoor cotton fabrics in both uniforms and tents. 

In the 1990s, two types of flame retardants are preferred for outdoor fabrics, ie, a system based on phosphoms and nitrogen such as the precondensate—NH finish and an antimony—bromine system based on decabromodiphenyl oxide [1163-19-5] and antimony(III) oxide (20,40—42). 

The tetramethylol derivative of DABT, prepared by reaction of DABT with alkaline aqueous formaldehyde, polymerized readily on cotton. It imparted excellent flame retardancy, very durable to laundering with carbonate- or phosphate-based detergents as well as to hypochlorite bleach. This was accomphshed at low add-on without use of phosphoms compounds or antimony(III) oxide (75—77). 

Another approach to durable press—flame retardancy uses a combination of a cross-linking system, antimony(III) oxide, and a bromine-containing reactive additive, namely dibromoneopentyl glycol, to achieve dual properties (120,121). 

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... 

Flame retardants such as a-alumina trihydrate [14762-49-3] can be added to latex-based foamed carpet backing a combination of antimony oxide [1309-64-4] and chlorinated paraffins is used in dry mbber. 

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