Flame retardant polyolefin

It has been shown that the required loading levels of metal hydroxides to flame retard polyolefins can be reduced by the addition of transition metal oxides as synergistic agents. For example, a combination of 47.6% MH modified with nickel oxide in PP gave a UL94 V-0 flammability rating, which would require -55% of unmodified MH.4 These systems, however, can only be used where the color of the product is not important. 

Hitachi Cable Ltd., Manufacture of halo-free flame-retardant polyolefin-covered electric wires, Japanese... 

Namike,Y., Kato, Y., Kitano, Y., Kuriso, H., and Yokata, Y., Flame retardant polyolefin compound having low smoking and toxicity, U.S. Patent No. 5,654,356, August 5, 1997. 

Marosi, G., Anna, P., Marton, A., Bertalan, G., Bota, A., Toth, A., Mohai, M., and Racz, I. 2002. Flame-retarded polyolefin systems of controlled interphase. Polymers for Advanced Technologies 13 1103-11. 

Stuart, J.B. Skarke, S.C. Ogita, T. et al. Flame retardant polyolefin resin pre-expanded particles and in-mold foamed articles prepared therefrom, PCT US Patent 6,822,023 assigned to Kaneka Corporation, 2001. 

FIGURE 26.4 Probability for flame spread versus heat release capacity of compounds. (Cogen, J.M. et al., Correlations between pyrolysis combustion flow calorimetry and conventional flammability tests with halogen free flame retardant polyolefin compounds, Fire Mater., 2009, 33, 33-50.)... 

After PVC, polyolefins are the next most widely used material for FR applications in wire and cable. They have very good dielectric strength, volume resistivity, mechanical strength, low temperature flexibility, and water resistance. In contrast to PVC, polyolefins are not inherently FR and thus are more highly formulated, requiring the addition of FRs to meet market requirements for flame retardancy. Polyolefins are experiencing extensive interest as the trend toward halogen-free materials continues to build. 

Qiang, W., Jianping, 1., Baojun, Q., 2003. Preparation and characterization of microencapsulated red phosphoms and its flame — retardant mechanism in halogen free flame retardant polyolefins. Polymer International 52 (8), 1326—1331. 

To cover the 1987 NEC (National Electric Code) flame and smoke performance guidelines which took effect in the U.S., industry generally uses a non-flame-retardant polyolefin as the insulation material and a highly flame-retardant PVC as the jacketing. If greater flame retardancy is required, fluoropolymers can be incorporated in the system. 

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. 

Firebrake zinc borates display an interaction with metal oxide partieles resulting from dehydrating metal hydrates in flame retardant polyolefins. The interactions taking place show that surface... 

Barenberg, S. A. Special Report Biomaterials. Medical Device Diagnostic Industry, pp. 81-87, Mar. 1990 Pawar, P. Flame-Retardant Polyolefins Don t Need Halogen. Plastics Trends, pp. 75-79, Mar. 1990. 

Okada, K. (Sekisui Chemical Co. Ltd.). Flame-retardant polyolefin resin composition. Jpn. Patent JPl 1228748, Aug. 24, 1999. 

Wu, Q. Lu, J.P. Qu, B.J. Preparation and characterization of microcapsulated red phosphorus and its flame-retardant mechanism in halogen-free flame retardant polyolefins. Polym. Int. 2003, 52(8), 1326-1331. 

Green, J. Flame retarding polyolefins. Meeting of Society of Plastic Engineers, San Francisco, 1974... 

Stearate Treated Magnesium Hydroxide for Flame Retardant Polyolefin and PVC Applications... 

In flame retarding polyolefins, typically, 40% orga-nochlorine can be replaced by 8% organochlorine-f 5% antimony oxide, or 20% organobromine can be replaced by 6% organobromine-1-3% antimony oxide [27]. Consequently, almost all polyolefin formulations based on organic halogen also contain antimony oxide to make it as effective as possible (Table 4). 

Flame retardant additives are reactive, which means that they are less stable than the polymers they may decompose during normal processing and/or use. This limits the choice of additives that can be used, and it further limits the processing conditions that may be used. These additives are particulate fillers. Large amounts are needed to flame retard polyolefins they are difficult to disperse uniformly and they result in serious stiffening and even embrittlement, particularly in PP. 

Hindered benzoate recommended for halogenated flame retardant polyolefin applications. 

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