The Many Applications of Antimony Oxide
by: Victor Lezo on Fri, 17 Apr 2009 at: 12:19 PM Go to: Previous Article Next Article
Antimony trioxide is the main derivative of antimony metal. The metal is mined most often in China, Bolivia, Russia, and South Africa. The oxide derivative can be used in many different industries including the flame retardant industry as a synergist, the plastic manufacturing industry as a catalyst, the glass industry as a clarifying agent, and in porcelain and enamel as an opacifier or white pigment.
If you want to flame retard something the most common additives for doing so is a halogenated compound in combination with a synergist. The halogenated compound alone will provide flammability protection, but the presence of the synergist allows you to use much less halogenated product. You can use approximately half as much halogen if you also use an antimony synergist.
The antimony/halogen combination is used to flame retard a great variety of materials. You will find antimony used in the plastics, textiles, rubber, paper, and paint industries. Specific materials that use an antimony synergist include but are not limited to high impact polystyrene (HIPS), polyvinyl chloride (PVC), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polyethylene (PE), propylene diene M-class rubber (EPDM), epoxies, phenolics, and polyurethanes.
Since halogenated compounds are usually sold in multi-walled paper bags then the antimony trioxide is typically sold that way too. If you use very large quantities then you can also buy the synergist in large tote bags. If you do not want to deal with powders, some specialty flame retardant firms will provide a liquid dispersion with the halogenated compound and antimony trioxide in the appropriate ratios mixed with whatever liquid is appropriate for your process.
Polyethylene terephthalate or PET is manufactured using a catalyst and often that catalyst is antimony trioxide. This polymerization process usually requires a more pure grade of antimony than flame retardant applications. Antimony is used more often than other catalysts because of the excellent cost to performance ratio. There are other options that provide better throughput, but they are much more expensive than antimony trioxide.
PET is used to make water bottles and other liquid containers. Because these liquids can sit in the bottle for a long time before consumption, there are some concerns about materials in the PET migrating into the PET. There have been some studies that show antimony will migrate into bottled water, but the concentrations are well below the level where we should be concerned. In addition, the toxicity of antimony is very low and its presence will not likely cause much harm.
The glass industry is another place you will find antimony trioxide being used. Trivalent antimony oxide is used as a clarifying agent. The clarifying agent is added during the meltdown part of the glass making process. The agent will help to eliminate bubbles and inclusions. It also is what makes the glass clear. If you didn't add any clarifying agent then the natural impurities in sand would make glass appear light blue or light green in color. Antimony trioxide unlike other clarifying agents does not cause any coloration at any time. Manganese oxide will make the glass clear initially, but exposure to ultraviolet light from the sun will cause the manganese to react and turn the glass purple.
As a consequence of its color, white, antimony can also be used as a pigment. One industry that utilizes it this way is the porcelain and enamel industry. Here, the antimony is used as an opacifier in very specific instances. As you can see, the uses of antimony are quite varied and many industries utilize this unique chemical compound.
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Antimony oxide makes most flame retardants fifty percent more effective. Contact Amspec for all your FR needs.
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