Cycloaliphatic flame retardants

Chlorinated aromatic products are relatively stable and therefore not very efficient, but chlorinated aliphatic and cycloaliphatic flame retardants are well... 

Chlorines Chlorinated paraffins Tris (dichloropropyl) phosphate, methyl pentachlorostearate, and other chlorinated phosphates Cycloaliphatic chlorine Chlorendic anhydride LDPE film and flexible PVC Urethane foam and topical fabric Polypropylene and nylon Reactive intermediate in making polyester and epoxy flame-retardant resins Amspec Chemical, Asahi Denka Kogyo, ICC Industries-Dover, Kettlitz Chemie, Lehmann Voss, OxyChem, Polytechs... 

Chlorine-containing flame retardants can be divided into three groups aliphatic, alicyclic (cycloaliphatic), and aromatic. Their thermostability is increased in this order, bnt flame retardant efficiency is decreased in the same order. This reciprocal tendency is common among flame retardants. Clearly, the higher the thermal stability, the higher the temperatnre at which the flame retardant becomes chemically active and fnnctional as a flame retardant. 

An example of cycloaliphatic chlorine flame retardants is hexachlorocyclo-pentadiene (Dechlorane Plus , or CFR). It is typically used in polyester resins in which hexachlorocyclopentadiene is converted into functional derivatives by maleic anhydride to give the net anhydride. It is the most stable chlorinated flame retardant (CFR). CFR is commonly used in synergism with antimony oxide, zinc borate, zinc oxide, and iron oxides. In Nylon 66, CFR is often used in concentrations of 8-25%, along with 1-10% of Sb203, zinc borate, or iron oxide [11]. 

Dimethanodil)enzo-(a,e)cydooclane, 1,2,3,4,7,8,9,10,13,13,14,14-dodeca-chloro- 1,4,4a,5,6,6a,7,10,1 Oa, 11,12,12a-dodecahydro-1,4 7,10-Dimethanodiben2o(a,e)oyolooctene, EINECS 236-948-9. Chlorine-containing cycloaliphatic comp-ound. Used as a flame retardant in polymer systems (thermoplastics, thermosets and elastomers) usually combined with antimony oxide as a synergist. Colorless crystals mp >326° soluble in o-dichlorobenzene LDso (rat orl) = 25 g/kg. OxyChem. 

Highly efficient and versatile for wide range of applications. Requires uses of antimony oxide. Broad range of high-performance products available, as aromatic, cycloaliphatic, and bromine/chlorine paraffins. Vapor-phase flame-retardant mechanism. Flame-retardant elements interrupt chemical reactions of combustion in flame zone. 

The following cycloaliphatic compounds are suitable as flame retardants in polyolefins hexabromo-cyclododecane and bromine-containing Diels-Alder reaction products based on hexachloro-... 

Chlorinated polyether Polysulphone Polytetrafluoroethylene Epoxy resin, amine-cured Epoxy resin, anhydride-cured The same filled with 65% of quartz flour The same filled with 65% of Al(OH)8 Epoxy resin, glass-laminated Epoxy resin, cycloaliphatic Expanded polystyrene Expanded polystyrene, flame-retardant Expanded polystyrene, extruded profile The same with flame-retardant Rigid polyurethane foam The same with flame-retardant Polysiocyanurate foam Flexible polyurethane foam Paraffin (candle)... 

Flame retardants containing bromine are twice as effective as those containing chlorine. However the price is higher and the UV resistance is lower. The products containing bromine are of aliphatic, cycloaliphatic, aromatic and aromatic-aliphatic type. Tetra-bromobisphenol A (TBBA) is condensed as a flame retardant in PC and expanded polystyrene (EPS). In phenolic and unsaturated polyester (UP) resins di- and tri-brominated phenols and tetra-bromophthalic anhydride serve as reactive components in the resin backbone. 

A broad range of halogenated flame retarding compoimds can be used in conjunction with antimony trioxide, typically chlorinated paraffins and chlorinated cycloaliphatic compoimds, brominated aromatic compounds and brominated phosphates. However, the major application for antimony trioxide in terms of consumption is in flexible PVC, where the chlorine available from the polymer is sufficient to provide the desired level of flame retardancy. 

In the past, polyethylenes were generally flame-retarded with chloroparaffins and antimony trioxide. Frequently PVC or chlorinated polyethylene was also added. Nowadays cycloaliphatic (hexabromocyclododecane) and aromatic bromine compoimds such as polybromodiphenyl ethers, and in particular decabromodiphenyl ether are used. Antimony trioxide is also used here as a synergist. 

Antimony oxide works synergistically with reactive or additive halogenated compounds to improve the flame-retarding effect of the halogens so that less of the halogenated compound needs to be used, with consequently less effect on physical properties. Antimony oxide is effective when used in combination with such organic flame-retardant compounds as chlorinated paraffins, chlorinated cycloaliphatics, aromatic bromine compounds, alkyl chlorine, or bromine and phosphates. It is used in such resins as ABS, polyethylene, polypropylene, polystyrene, thermoplastic polyester (PBT), and unsaturated polyesters. 

Flame retardants are required for high-performance thermoplastic resins because of the use of the resins in electrical and high-temperature applications. Numerous chemicals are used as flame retardants. Chlorine-and bromine-containing aliphatic, cycloaliphatic and aromatic compounds are the most widely used. Others are antimony trioxide, aluminum hydrate and chlor-paraffins. A more fire-resistant epoxy resin can be produced by bromating bisphenol A in epoxy resins to tetrabromobisphenol A. 

In the vicinity of a flame, the foam fuses and burns like plastic PS with a luminous yellow, sooty flame and a sweetish odour. It burns until the ignition source is removed. The introduction of flame retardant makes PS foams less flammable. Compared with PS plastic which is processed at temperatures up to 260 °C, the manufacture of expanded PS is carried out at around 120 °C and the extruded PS foam is produced at about 260 °C. These conditions enable the less thermally stable aliphatic and cycloaliphatic bromine flame retardants to be used [33]. 

A free-flowing white powder, Dechlorane Plus contains 65 percent chlorine in a cycloaliphatic confound, ideal for imparting flame retardant properties to thermoplastics, thermosets and elastomers. As the only stable chlorinated flame retardant on the market, Dechlorane Plus is usually combined with antimony oxide (Sb203), but in some resins can be used with other synergists. 

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