Epoxies flame retardants

The preparation of flame-retardant epoxy resins is accompanied by inclusion of tetrabromobisphenol A [79-94-7] in the advancement process (see Flame retardants). Products containing ca 20 wt % Br are extensively employed in the printed circuit board industry. 

The major commercial alternative to DOPO and its derivatives for reactively flame retarding epoxy resins, especially for electronic applications, is an oligo(l,3-phenylene methylphosphonate) (Structure 5.18) marketed by Supresta under the tradename Fyrol PMP. Fyrol PMP has a functionality higher than that of DOPO and can be used either as a hardener (curing agent) or be precondensed with an epoxy. 

Lin, C. H., Cai, S. X., and Lin, C. H., Flame-retardant epoxy resins with high glass-transition temperatures. II. Using a novel hexafunctional curing agent 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-yl-tris(4-aminophenyl) methane, J. Polym. Sci., Part A Polym. Chem., 2005, 43, 5971-5986. 

Ren, H., Sun, J., Wu, B., and Zhou, Q., Synthesis and properties of a phosphorus-containing flame retardant epoxy resin based on bisphenoxy(3-hydroxy) phenyl phosphine oxide, Polym. Degrad. Stab., 2007, 92, 956-961. 

Flame-retardant epoxy resins with different silicon contents were prepared using silicon-containing epoxides or silicon-containing prepolymers. The thermal stability and flame-retardant properties of the produced epoxide systems were evaluated and related to the silicon content. The char yields under nitrogen and air atmospheres increased with increase in silicon content. The authors pointed out that the silicon-containing resin has improved flame retardancy over the silicon-free resin as evidenced by the LOI. LOI values increased from 24 for a standard commercial resin to 36 for silicon-containing resins.35... 

Toldy, A., Anna, P., Csontos, I., Szabo, A., and Marosi, Gy. 2007. Intrinsically flame retardant epoxy resin—Fire performance and background—Part I. Polymer Degradation and Stability 92(12) 2223-2230. 

Shieh JY, Wang CS. Synthesis of novel flame retardant epoxy hardeners and properties of cured products. Polymer 2001 42 7617-7625. 

Liu YL. Flame-retardant epoxy resins from novel phosphorus-containing novolac. Polymer 2001 42 3445-3454. 

Braun U, Balabanovich AI, Schartel B, Knoll U, Artner J, Ciesielski M, Doring M, Perez R, Sandler JKW, Altstadt V, Hoffmann T, Pospiech D. Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites. Polymer 2006 47 8495-8508. 

Schartel B, WeiB A, Mohr F, Kleemeier M, Hartwig A, Braun U. Flame retarded epoxy resins by adding layered silicate in combination with the conventional protection layer building flame retardants melamine borate and ammonium polyphosphate. J. Appl. Polym. Sci., 2009, submitted. 

Meath, A. R. Chemistry, Properties, and Applications of Epoxy Novolac, Flexible Epoxy, and Flame Retardant Epoxy Resins, Chapter 3 in Epoxy Resin Technology, P. F. Bruins, ed., Interscience Publishers, New York, 1968, p. 34. 

Meath, Chemistry, Properties, and Applications of Epoxy Novolac, Flexible Epoxy, and Flame Retardant Epoxy Resins, p. 38. 

Selecting a flame retardant for an adhesive system has many ramifications, depending on the formulation being modified, the end use, how it will be processed, and the cost/performance ratio. When one is choosing a flame retardant, characteristics such as water extraction, particle size, viscosity, toxicity, dusting, uniformity, as well as economics must be considered. The materials chosen to perform the function of flame retardation must not interfere with the final product s performance. The major problem with incorporating flame retardants in adhesives is that very often a significant amount is required, and they interfere with the other properties of the adhesive and contribute to the cost. This is why bromo bisphenol epoxy resins are often employed in flame-retardant epoxy adhesives. 

Pyrolysis Products of Flame-retarded Epoxy Resin... 

The matrix material for the laminates for this investigation was a typical flame retardant epoxy resin system used in PWB technology. The epoxy resin was a brominated diglycidyl ether of bisphenol-A cured with dicyandiamide and catalyzed by benzyl dimethylamine. 

K. Kampke-Thiel, et al., Isolation, characterization, and toxicological aspects of volatile organophosphorus compounds from the combustion of flame-retarded epoxy resins with phosphonate substructures. Chem. Eur. J. 1998, 4(8), 1581-1586. 

As in polyester resins, reactive halogens containing fire-retardant chemicals are most often used in epoxy materials. Tetrabromobisphenol A is perhaps the most widely used component for flame-retarding epoxy resins. Nara and Matsuyama (24) and Nara et al. (25) described the thermal degradation and flame retardance of tetrabrominated bisphenol A diglycidyl ether compared to the nonbrorainated structure. Their results indicate that bromine acts by vapor-phase as well as condensed-phase mechanisms of flame inhibition. 

CMD. pUione-Poulenc] l xy, polyamide, or aaylic resin sd ns. us for industrial coatings, flame-retardant epoxy conqxls. 

Phenolphthalein (213) and its derivatives have found application in the polymer area. Phenol-phthalein itself (213) and substituted derivatives were polymerized with 2,6-dichlorobenzonitrile to form heat-resistant polycyanoaryl ethers <89JAP(K)01225631). A tetrabromo derivative (256) was polymerized with epichlorohydrin to form flame-retardant epoxy resins. The phthalide-derived... 

As FAA flammability requirements have changed in the past, both epoxy and polyurethane materials have been reformulated to comply with new regulatory standards and individual OEM aircraft demands. For example, the first flame-retardant epoxies included halogenated compounds and antimony oxide to reduce flammability. However, the presence of bromines generated high levels of smoke, making the products inappropriate for many cabin interior applications. 

P. F. Ranken, R. G. E. Herbiet Flame retardant epoxy prepregs, laminates, and printed wiring boards of enhanced thermal stability. Patent EP 1 670 860 Bl. Publication date 06.05.2005... 

Uses Reactive flame retardant for epoxies, phenolics, ABS, HIPS, unsaturated polyesters, PC, adhesives, coatings, textiles fire-retaidant PC comonomer mfg. of flame-retardant epoxies intermediate for flame retardants... 

MIcral 1000 MIcral 1500 Saytex 102E Saytex BT-93 Tetrabromobis (2-ethylhex ) phthalate, Uniplex FRP-45 flame retardant, epoxies AnUblaze 519 Antiblaze TCP AnUblaze TXP Antimony penloxide, Busan 11-Ml Ethylenehls (tetrabromophthallmide) FRCROS 480 FRCROS 481 FRCROS 485 Great... 

Lo, J. and Pearce, E. M. Flame-retardant epoxy resins based on phthalide derivative. /. Polym. Sci. Polym. Chem. Ed., 22, 1707 (1984)... 

The other important diol which finds wide application in synthesis of flame retardant epoxy thermosets is 4,4 -isopropylidene bis(2,6-dibromo-phenol) (tetrabromobisphenol-A,TBPA).The primary use of TBPA is as a reactive flame retardant in epoxy resin-based circuit boards and in electronic enclosures made of polycarbonate-acrylonitrile, butadiene-styrene, etc. Hexafluorobisphenol-A (bisphenol-AF, hexafluoroisopropylidene diphenol) has also been used for the synthesis of fluorinated epoxy resin aiming at the anticorrosion coatings market for industrial vessels and pipes. The key disadvantages of fluorinated epoxies are their relatively high costs and low Tg, which limit their commercialisation. Thus utilisation of such diols in vegetable oil-based epoxy resins may result in similar performance. 

Environmentally friendly, bio-based flame retardant epoxy resins have been reported from a di-epoxy fatty compound, 10-[2, 5 -bis(9-oxiranyl-nonayloxy) phenyl]-9,10-dihydro-9-oxa-10-phosphaphenanthrene-l 0-oxide (Rg. 7.5a) and epoxidised 10-undecenoyl triglyceride and epoxidised methyl-3, 4, 5-tris(10-undecenoyloxy)benzoate (Hg. 7.5b and c). The limiting oxygen index (LOI) values of the cured products indicate good flame retardant behaviour owing to the formation of a protective phosphorous-rich layer which slows down degradation and protected the products. 

G. Das and N. Karak, Vegetable oil ased flame retardant epoxy/clay nanocomposites , Polym Degrad Stab, 2009, 94,1948-54. 

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