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Injection moulded parts consume a considerable amount of various flame retardants due to their application in the
electrical and electronic industry. Flame retardants save many lives and property because they prevent accidental
fires. However, several concerns related to chemical release into the environment and potential health effects
shroud these additives. Since halogenated flame retardants have been in the focus of public scrutiny, flame
retardants based on other chemistries like phosphorus and nitrogen have been developed and need to prove their
environmental benefits.
Phosphorus chemicals are known as flame retardants. However, their mechanism to prevent fire is different. First of
all the phosphorous content of different chemicals vary from as low as 9.5% in case of TCP to as high as red phosphorus.
Besides, the phosphorus atom is found in oxidation states ranging from 0 to 5. Typically, phosphorus based flame retardant
is designed to develop its activity in combination with the starting decomposition of basic polymer. It can offer a partial
gas phase contribution to the flame extinguishing effect which is comparable to brominated flame retardants. However, the
main feature is char forming activity sometimes combined with foaming or intumescences, which forms a protective top layer
on the surface. This type of solid phase mechanism provides an advantage of less release of smoke and gases in case of fire
situation.
Among all different types of phosphorus flame retardants, organic phosphinates are quite efficient and can be used to
develop polymer products with V0 fire resistant properties despite their lower phosphorus contents. Phosphinates also
have excellent thermal stability. This type of flame retardant has a very low solubility in water and can be effectively
used in polyamides without them losing their inherent properties. This type of phosphorus flame retardant provides
synergetic effect with melamine flame retardants.
Polyester thermoplastic products can be very effectively developed to achieve V0 rating with phosphinate. However
it has different synergy system & does not require melamine flame retardant for synergy. Polyolefins also can
achieve V0 flame retardant property with phosphinates.
Organic phosphinates are a newly developed class of flame retardants for engineering thermoplastics, and are especially
effective for polyamides and polyesters. Different polyamides, especially glass fibre reinforced grades, can be
effectively fire retarded with these new halogen-free products based on the phosphinates. The required dosage for
a UL 94 V-0 performance is lower than for other flame retardant formulations apart from red phosphorus.
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