Phosphorus-based thermoset

The largest volume use of phosphorus-based flame retardants may be in plasticized vinyl. Other use areas for phosphorus flame retardants are flexible urethane foants. polyester resins and other thermoset resins, adhesives. textiles. polycarbonate-ABS blends, and some Other thermoplastics. Development efforts are well advanced lo find applications for phosphorus flame retardants, especially ammonium polyphosphate combinations, in polyolefins, and red phosphorus in nylons, Interest is strong in finding phosphorus-bused alternatives to those halogen-containing systems which have encountered environmental opposition, especially in Europe. 

Antlblaze 1045 Flame Retardant Is a unique phosphorus based product Intended for the plastics Industry. Both thermoplastic and thermoset applications with demanding performance requirements can benefit from the use of this additive product. The balance of properties which characterize Antiblaze 1045 Flame Retardant are unique. 

These are mainly relevant to thermosetting resins, such as unsaturated polyesters and epoxies. For polyesters, the main reactive retardants are HET acid (based on chlorine) or dibromoneopentyl glycol (DBNPG). Brominated FRs are said to be 70% more efficient than HET acid (which has also become expensive). With epoxies, the best system (on present evidence) appears to be reactive phosphorus organic compounds, which are toxicologically harmless in fire and are chemically linked to the resin matrix, so that mechanical and chemical properties are not affected. 

Polycondensation of Compounds Containing a Phosphate Linkage. Polycondensation of tris(2-chloroethyl) phosphate, preferably in the presence of a nucleophilic catalyst, affords an oligomeric phosphate which was for a time produced by this process as a flame retardant for polyurethane foams, thermoset resins, and air-fllter products (140-142). A preferred method, avoiding a chlorinated coproduct, is based on addition of phosphorus pentoxide and ethylene oxide to the tris(2-chloroethyl) phosphate, as discussed above. 

In general purpose applications competitively priced thermosets are used for the printed circuit board base material which is usually FR4 (Flame Retardant) . One of the main flame retardants used in America is to have tetrabromobisphenol-A reacted into the epoxy resin. Non-halogen systems include additives such as alumina trihydrate, alumina trihydrate/red phosphorus and aromatic phosphates. Flame retardant epoxy coatings are reported to use ammonium polyphosphate with char-forming additives. 

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