Keep an eye out for all-new inherently flame-retardant engineering compounds developed for electronics applications.
Growing regulatory review of brominated compounds is spurring new development from both resin and additive producers.
One interesting product is a newly patented polyphosphonate from FRX Polymers that is transparent and a close cousin to polycarbonate. These new polymers are nonburning specialty materials that can actually improve mechanical properties in compounds.
"While much research has been done on polyphosphonates over the last 50 years, FRX Polymers is the first company to commercialize them," says founding CEO Marc Lebel. "We have developed a cost-effective manufacturing route and through intensive research efforts over the last 4 years we have dramatically improved the properties of these polymers."
FRX is working with major polymer and FR additive manufacturers and has also developed the synthesis process for one of the key phosphorous-containing monomers used to produce polyphosphonates.
Flame retardance is usually achieved through addition of chemicals that can reduce component properties. But that's not the big reason a push is underway to develop FR alternates. New regulations characterize all chemical substances in use in terms of their environmental and human health impacts. And 2008 was a watershed year for FR regulation. The first steps in the European REACH program took place with pre-registration of chemicals completed by Dec. 1. The California Green Chemistry Initiative gained momentum. And flame-retardant chemicals remain a focus for specific regulatory developments such as the European Union's RoHS directive 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 (decabromodiphenyl ether) and octa-BDE, have been banned in the European Union. Use of decabromodiphenyl ether will be banned from use in computer and television housings starting next year in Maine. The State of Washington is also considering restrictions on use of deca-BDE.
Producers of brominated chemicals, such as Albemarle, say there are several problems with alternatives, including:
- They typically do not have same amount of testing;
- Reliability has not been confirmed in use;
- They require costs for conversion;
- Product availability is uncertain and they are
- Generally higher in cost.
Some of these arguments are slowly losing ground as new technologies emerge, many of them proprietary and highly secretive. In fact, virtually every major supplier of engineering compounds for electronic applications has introduced nonbrominated and nonhalogenated alternates, many with improved mechanical properties. Some have as many as two or three years of field testing.
LNP Starflam compounds from Sabic Innovative Plastics are said to have mechanical and electrical properties that exceed those of traditional materials using brominated and red phosphorus additives.
"Until now, there were no good alternatives to traditional reinforced polyamides," says Nitin Apte, general manager of LNP when the new materials were introduced.
The LNP Starflam X-Gen Z270 compounds combine non-halogenated flame retardance and low smoke performance and meet UV94 V-0 standards at low thicknesses as well as IEC60335 requirements. Sabic IP is introducing new forms of high-performance, inherently flame-retardant Ultem polyetherimide (PEI) resins, film and fiber/foam composites at the National Plastics Exposition in Chicago June 22-26.
BASF is introducing Elastollan 1190 A 10 FHF, a new halogen-free, flame retardant grade of TPU for wire and cable applications. Attributes of the new TPU are said to be excellent abrasion resistance, low temperature properties, hydrolytic stability and fungus resistance.
The new halogen-free TPU complements a line of BASF halogen-free materials that are available in a broad range of hardnesses (80 Shore A to 54 Shore D).
A new 25-percent glass fiber-reinforced nylon 6 compound that provides an alternative to halogenated flame retardant will be introduced at the NPE by Chem Polymer, a unit of Teknor Apex Company.
"Because non-halogenated FR systems have been more difficult to incorporate into glass-filled compounds than brominated ones, relatively few non-halogenated nylons have been available in North America," says Richard Barnes, technical manager. "Our new Chemlon compound will provide a higher performance alternative for North American molders seeking to serve the world market for components requiring flame retardancy."
In May, Ticona Engineering Polymers announced a new low-chlorine liquid crystal polymer alloy grade to its portfolio of V-0 halogen-free polymers. The new grade is inherently flame resistant and can withstand high surface-mount technology soldering temperatures used in the electrical and electronics industry.
Both Vectra LCP and Fortron linear polyphenylene sulfide offer inherently flame-resistant properties without the use of halogenated or non-halogenated flame retardants.
