Quimica, Chemical: Halogenated flame retardants

While the environmental impact of halogenated flame retardants continues to be scrutinized, both brominated and chlorinated flame retardants used in PA are expected to continue to have good growth, say suppliers. The polymeric brominated flame retardants typically used in PAs are not extracted from the polymer matrix, reducing concerns about their environmental effect. OxyChem's Dechlorane Plus® chlorinated alicyclic compound is non-blooming and does not form chlorodibenzodioxins or furans. Dechlorane Plus® has good thermal stability and can be processed up to 320°C.

Great Lakes introduced a new brominated polystyrene, Firemaster BP411, for electrical components in January 2004. Albemarle recently introduced Saytex HP-3010, a brominated polystyrene with improved colour stability, thermal stability, and high flow. The new product is targeted for high-temperature polyamides and high-flow applications such as complex, thin-wall parts, notes Sam Thomas, flame retardants global business manager for connectors at Albemarle Corporation. ICL Industrial Products, formerly the Dead Sea Bromine Group, recently introduced F-3100, a high molecular weight polymeric brominated flame retardant for glass-reinforced engineering resins. The product is expected to reduce energy consumption during compounding and pressure during injection moulding, as well as have good melt flow during recycling, says the company. ICL-IP has also introduced the SaFRon 5500 series, proprietary polymeric flame retardants with anti-drip properties, and SaFRon 5251, a dust free polymeric flame retardant for improved conveying and feeding. These products have a processing-aid effect, enabling lower processing temperatures and enhancing melt flow, notes ICL-IP.

Great Lakes' Firemaster CP-44HF flame retardant was originally developed in 2003 to provide higher thermal stability and flow. With the movement to lead-free solder, the product has now been shown to offer improved blister resistance due to its compatibility with HTPA resins. Traditional flame retardants such as brominated polystyrene tend to form blisters on the part surface at the higher temperatures used during lead-free soldering. Blistering occurs because the flame retardant is not completely dispersed through the polymer, but clusters in flame retardant domains where moisture collects and then expands when exposed to high temperatures. Firemaster CP-44HF is a co-polymer of di- and tri-bromostyrene with glycidyl methacrylate. The methacrylate functionality allows greater bonding and compatibility of the flame retardant with the host resin, resulting in improved dispersion and elimination of the flame retardant domain, explains Mr. Andrews.