New Chemistries Emerge for Flame-Retardant Applications

Keep an eye out for all-newinherently flame-retardant engineering compounds developed for electronicsapplications.

Growing regulatory review ofbrominated compounds is spurring new development from both resin and additiveproducers.

One interesting product is a newlypatented polyphosphonate from FRXPolymers that is transparent and a close cousin to polycarbonate. These new polymers are nonburning specialty materialsthat can actually improve mechanical properties in compounds.

"While much research has been done on polyphosphonatesover the last 50 years, FRX Polymers is the first company to commercialize them,"says founding CEO Marc Lebel. "We have developed a cost-effectivemanufacturing route and through intensive research efforts over the last 4years we have dramatically improved the properties of these polymers."

FRX is working with major polymerand FR additive manufacturers and has also developed the synthesis process forone of the key phosphorous-containing monomers used to producepolyphosphonates.

Flame retardance is usuallyachieved through addition of chemicals that can reduce component properties.But that's not the big reason a push is underway to develop FR alternates. Newregulations characterize all chemical substances in use in terms of theirenvironmental and human health impacts. And 2008 was a watershed year for FRregulation. The first steps in the European REACH program took place withpre-registration of chemicals completed by Dec. 1. The California GreenChemistry Initiative gained momentum. And flame-retardant chemicals remain afocus for specific regulatory developments such as the European Union's RoHSdirective and state legislation in the USA.

Primary issues under review are bioaccumulation, toxicity,environmental persistence and emissions during combustion.

Two brominated FR additives, penta-BDE (decabromodiphenylether) and octa-BDE, have been banned in the European Union. Use of decabromodiphenylether will be banned from use in computer and television housings starting nextyear in Maine.The State of Washingtonis also considering restrictions on use of deca-BDE.

Producers of brominated chemicals, such as Albemarle, say there are several problems withalternatives, including:

Some of these arguments are slowly losing ground as newtechnologies emerge, many of them proprietary and highly secretive. In fact,virtually every major supplier of engineering compounds for electronicapplications has introduced nonbrominated and nonhalogenated alternates, manywith improved mechanical properties. Some have as many as two or three years offield testing.

LNPStarflam compounds from Sabic Innovative Plastics are said to have mechanicaland electrical properties that exceed those of traditional materials using brominatedand red phosphorus additives.

"Until now, there were no good alternatives to traditionalreinforced polyamides," says Nitin Apte, general manager of  LNP when the new materials were introduced.

The LNP Starflam X-Gen Z270 compounds combinenon-halogenated flame retardance and low smoke performance and meet UV94 V-0standards at low thicknesses as well as IEC60335 requirements. Sabic IP isintroducing new forms of high-performance, inherently flame-retardant Ultempolyetherimide (PEI) resins, film andfiber/foam composites at the National Plastics Exposition in Chicago June 22-26.

BASF is introducing Elastollan1190 A 10 FHF, a new halogen-free, flame retardant grade of TPU for wire andcable applications. Attributes of the new TPU are said to be excellent abrasionresistance, low temperature properties, hydrolytic stability and fungusresistance.

The new halogen-free TPU complements a line of BASFhalogen-free materials that are available in a broad range of hardnesses (80Shore A to 54 Shore D).

A new 25-percent glass fiber-reinforced nylon 6 compoundthat provides an alternative to halogenated flame retardant will be introducedat the NPE by ChemPolymer, a unit of Teknor Apex Company.

"Because non-halogenated FR systems have been more difficultto incorporate into glass-filled compounds than brominated ones, relatively fewnon-halogenated nylons have been available in North America," says Richard Barnes, technical manager. "Our new Chemloncompound will provide a higher performance alternative for North Americanmolders seeking to serve the world market for components requiring flameretardancy."

In May, Ticona Engineering Polymers announced a newlow-chlorine liquid crystal polymeralloy grade to its portfolio of V-0 halogen-free polymers. The new gradeis inherently flame resistant and can withstand high surface-mount technologysoldering temperatures used in the electrical and electronics industry.

Both Vectra LCP and Fortron linear polyphenylene sulfide offerinherently flame-resistant properties without the use of halogenated ornon-halogenated flame retardants.

New Chemistries Emerge for Flame-Retardant Applications A