Flame retardant nonhalogen cables

The additives business has been at the centre of environmental controversies for many years, and has made strenuous efforts to improve its products. Flame retardants for cable and wire insulation are increasingly made of nonhalogen, low-smoke materials, and there has been increased usage of phosphorus and metal hydroxide flame retardants in recent years. Major changes have also taken place in the heat stabiliser business, with lead compounds being voluntarily phased out over several years. 

Compounds with halogenated flame retardants are often used to pass this test, but more and more flame retardant nonhalogen (FRNH) cables are demanded by the market for the... 

Flame-Retardant Filler. Demand has increased for Mg(OH)2 as a nonhalogenated, flame-retardant filler for thermoplastics used in the aerospace, microelectronics, and cable and wire manufacturing industries (90). Producers of nonhalogenated, flame retardant fillers include Kyowa, Aluisuisse-Lonza (Magnifin product line), Morton, and a Dead Sea Periclase/Dead Sea Bromine joint venture (91). 

WEEE has had a direct affect on flame-retardant use, because flame retardants are used in almost all electrical and electronic equipment to prevent fires from short circuits. This directive lays down rules for disposal and recycling of all electrical and electronic equipment that goes back to the previous incinerator discussion. For flame retardants, this directive affects how the plastic parts, cable jackets, and enclosures are flame retarded. If the plastic cannot be reground and recycled, it must go to the incinerator, in which case it cannot form toxic by-products during incineration. This has led to the rapid deselection of brominated FR additives in European plastics that are used in electronics, or the complete removal of FR additives from plastics used in electronics in Europe. This led, in turn, to increases in electrical fires in Europe, and now customers and fire-safety experts demand low environmental impact and fire safety. However, the existing nonhalogen flame-retardant solutions brought in to replace bromine have their own balance-of-property issues, and so research continues to develop materials that can meet WEEE objectives. 

Chem. Descrip. Nonhalogen nitrogen/phosphorus Uses Flame retardant for polyolefin and PU applies, incl. PP battery cases and electronic housings, PE wire/cable and molded parts, PU flexible foam and paints/coatings... 

There has been growing demand for nonhalogen, low smoke polymers for wire and cable insulation and sheathing. These products can be polyolefins with nonhalogen flame retardants, often metal hydroxides. DuPont markets a maleated compatibiliser under the name Fusabond to compatibilise polyolefins with the inorganic flame retardants, ATH and magnesium hydroxide, as well as with mineral fillers like calcium carbonate. 

The primary use for Vamac in wire and cable is in ATH filled, flame resistant, nonhalogen jackets, usually peroxide cured (Table 6.32). The following typical jacket compounds are based on Vamac D and Vamac G. A color concentrate can be used in place of the carbon black. Armeen 18D and Vanfre VAM can be added to improve release properties but at the high filler levels associated with flame-retardant jacketing compounds, release is usually not a problem. 

---