Halogenated flame-retardant plasticizer

A halogenated flame-retardant plasticizer is produced by Uniplex, containing bromine and chlorine. It improves low-temperature brittleness and provides lower smoke than conventional brominated phthalate diesters, for use primarily in wire and cable applications of flexible PVC, EPDM, and thermoplastic olefins. 

Addition of approximately 40% of the halogen flame retardants are needed to obtain a reasonable degree of flame retardancy. This usually adversely affects the properties of the plastic. The efficiency of the halogens is enhanced by the addition of inorganic flame retardants, resulting ia the overall reduction of flame-retardant additive package and minimising the adverse effects of the retardants. 

Ba(B02)2 H2O, used in flame retardant plastic formulations as a synergist for phosphoms or halogen compounds and as a partial or complete replacement for antimony oxide (see Flame RETARDANTS), is excellent as an afterglow suppressant. The low refractive index of results in greater... 

Fractions containing halogenated flame retardants (e.g., from printed circuit boards, cable insulation, and plastic housings) must be incinerated in suitable plants if recycling is not possible. 

Minor industrial uses include the application of silver iodide as a smoke for the seeding of clouds to induce rainfall. Compounds used for obtaining some nonflammable plastics and cellulose are benzyltriphenyl-phosphoniumiodides and [2,-(acetyloxy)ethyl] triphenyl-phosphoniumiodides (see Flame RETARDANTS, HALOGENATED FLAME retardants) (142). The addition of iodine to an aromatic hydrocarbon such as -butylbenzene results in the formation of charge-transfer complexes that display outstanding effectiveness as lubricants for hard-to-lubricate metals (143), such as titanium or steels (see also LUBRICATION AND LUBRICANTS). Iodine is also used in the production of high purity metals such as titanium, silicon, hafnium, and zirconium (144). 

Flame-retardant styrenic polymers find utility in applications such as building insulation (expanded polystyrene foam) and electronic enclosures (flame-retardant HIPS, ABS and styrenic blends). The most effective flame retardants are halogen-(particularly bromine)-containing compounds these flame retardants act by inhibiting the radical combustion reactions occurring in the vapor phase. Flame-retardant plastics are in a state of flux, due to influences of... 

Halogenated flame retardants such as chlorinated paraffins, chlorocycloaliphatics, and chloro- and bromoaromatic additives, which are commonly employed in flame-retarding plastics, are postulated to function primarily by a vapor-phase flame-inhibition mechanism. Flame retardation could be implemented by incorporating fire-retardant additives, impregnating the material with a flame-retardant substance, or using flame-retardant comonomers in the polymerization or grafting. 

P. Moy. Recyclability of FR-PC/ABS composites using non-halogen flame retardants. In 15th International Conference ADDITIVES 2006, Plastics Additives for Special Effects, ECM, Plymouth, MI, Las Vegas, NV, January 30-February 1, 2006. 

Isarov A, et al. Non-halogen flame retardant polyolefin compounds via synergistic blends of metal hydroxides and mineral fillers. International Polyolefins, conference proceedings. Society of Plastics Engineers 2007. 

Chem. Descrip. Antimony oxide CAS 1309-64-4 EINECS/ELINCS 215-175-0 Uses Flame retardant for plastic, textiles, paper, and paint applies. Features Superfine grade high tinctorial str. used in conjunction with halogenated flame retarders... 

A novel flame retarding plasticizer is based on polyetltylene stibnite phosphate esters. It contains all essential elements present in compounds having flame retarding properties, such as Sb, P, and halogens. The plasticizer has the advantage of a uniform distribution of antimony oxide which is formed in situ but it is not sufficiently stable at elevated temperamres and to hydrolysis. " Low smoke generation was obtained with a novel plasticizer based on pentaerythritol. ... 

More usually, the plasticizer component of the formulation is replaced by flame-retardant plasticizers such as liquid chlorinated paraffins, acting as secondary plasticizers up to 30 per cent of the original plasticizer content. As an associate plasticizer, phosphoric esters are often used. The appropriate flame-retardance is achieved by adding 1 or 2 phr. of phosphorus to the compound. More rigid or more flexible cold-resistant products can be formulated with triaryl or trialkyl phosphates, respectively. Halogenated phosphates may also reduce the flammability of plasticized PVC. 

Tried-and-tested flame retardant systems based on bromine compounds will continue to be used, with just a few exceptions, on account of their outstanding price-to-performance ratio. This is clear from printed circuits, where halogen-free reactive and additive FR systems are not able to displace the FR4 laminates based on tetrabromobisphenol-A (TBBA). Such is the case in Europe, at least. The situation could prove to be different in Asia, since the giants in the sector, such as Sony, have committed themselves to halogen-free printed circuits. In Europe and Asia, iimovations in flame retardant plastics continue to be in the field of halogen-fi ee systems. 

Exolit flame retardants from Clariant do not use halogens to produce flame retardancy. They have a low smoke density and produce non-corrosive gases. Exolit materials can be combined with light stabilisers to provide good UV stability in flame-retarded plastics. The Exolit AP series for thermosets is used in combination with ATH to allow manufacturers to use UP and epoxy resins in lightweight components for trains and buildings. 

Moves to restrict the use of halogenated flame retardants are starting to have a dramatic impact on the way in which plastics are used in electronic equipment and the ability of electronic manufacturers to provide the consumer with higher levels of fire safety. Certain plastics may no longer be able to be used and, more importantly, the high levels of fire safety (such as UL94 5V and above) may no longer be readily achieved without additional material cost. 

Starting in Germany in 1993, requirements that excluded the use of halogenated flame-retardants and plastics for copiers, PCs and printers were introduced. These were given eco-labels ( Blue Angel Eco-label). TVs that did contain them were deprecated in consumer magazines. 

Metal hydroxides provide an important alternative to halogenated flame retardants. Aluminium trihydroxide, sometimes known as alumina trihydrate, is the most widely used of all FRs in plastics. Magnesium hydroxide is also finding increasing acceptance, and calcium hydroxide is being marketed as an additive for different reasons. 

A similar effect may be expected from the EU Directive WEEE (Waste Electrical and Electronic Equipment). This aims to control the use of certain materials and to encourage re-use and recycling of all electrical and electronic components (defined as that equipment which is dependant upon electric currents or electromagnetic fields in order to work properly ). For compounders, the immediate implication is to control the use of flame retardants, and a specific aim of the WEEE Directive is to reduce or eliminate halogenated flame retardant additives in the plastics compounds used for E and E products. The deadline for this is 2004, but there will obviously be much discussion as to which FRs should be phased out. 

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