The Best of Both Worlds

Aesthetics, environmental issues and higher resin performance standards are a few of the factors driving new developments in materials targeted for the electronics market.

Rhodia Engineering Plastics is introducing a new line of flame-retardant, polyamide resins without halogen or red phosphorus additives. Technyl Star S 60G1 V30 is a high-flow, 30% glass-filled, flame-retardant grade. The nylon-6 based resin is rated UL V0 and is designed to fit a wide spectrum of highly-demanding electrical applications, such as control switchgears, timers and connectors used in appliances and industrial electronics.

“This product takes our high-flow Technyl Star polyamide technology into the halogen-free market,” says Richard Reeves, Rhodia business manager E/E markets.

The new 60G1 V30 grade, which will be commercially available in June, passes the UL94 V0 test at 0.8 mm and Glow Wire at 0.8 mm, satisfying requirements for miniaturized components. Reeves says the Glow Wire test is becoming increasingly important in North America, and is already a required standard in Europe.

“The flame-retardant performance of this grade is as good as any brominated resin,” Reeves reports.

With a melt viscosity of 1.1, Technyl Star has a much higher flow than regular nylon 6. Lower viscosity means the molder can use lower injection pressures and a smaller tonnage press. It also means the material is capable of flowing into thinner wall sections, giving engineers the freedom to design more intricate parts.

“By incorporating thinner ribs and walls a molder is ultimately able to make a part with equal performance at a lower weight,” Reeves says.

IT’S NOT EASY BEING GREEN

Dow Plastics has produced a new ignition-resistant polystyrene (IRPS) resin. Styron A-Tech 6079 is made with a unique, proprietary rubber technology that provides superior flow characteristics and aesthetics compared with other IRPS resins, while retaining excellent toughness. The new resin, which replaces both Styron 6079 polystyrene and Styron A-Tech 2220 resin, Dow’s previous IRPS resins, is targeted for a wide range of consumer and business electronics applications.

According to Ernesto Pousada, Dow Plastics IRPS marketing manager, North America, the properties of Styron A-Tech 6079 make it ideal for larger applications designed with thinner walls and other complex features, such large-screen TV housings and information technology equipment. It also suitable for small, intricate parts used in portable electronic devices.

Dow says the new material’s flow characteristics, give the molder the potential to produce no-paint parts, which can save customers 10% or more in manufacturing costs.

“By using Styron A-Tech 6079 for all IRPS applications, OEMs can meet all performance requirements while simplifying their manufacturing and specification process,” says Pousada.

BASF’s Petra 330FR is ideally suited for injection molding bobbins, coils and similar electronic components. Formerly manufactured by Honeywell, this grade is a 30% glass-reinforced, flame-retardant PET with a UL V0 flame rating at 1/64 in. thickness.

Petra is made of 100% post-consumer and post-industrial PET and contains no halogenated dioxins, furans or brominated compounds. The material has high crystallinity, which imparts good processing characteristics. Petra is suitable for component electrical insulation applications under several UL-1446 classification systems.

AESTHETICS FUSED TO FUNCTION

Navitrak International Corporation’s Digital Navigation Assistant (DNA) is a shock- and water-resistant handheld global positioning satellite receiver that conforms to U.S. military specifications. The unit’s yellow housing is comprised of two injection molded PC/PET shells that are overmolded with black Santoprene TPV. The overmolding process creates an integral perimeter gasket on one-half of the shell, which provides the watertight seal.

Protoplast Inc. of Coburg, ON built the Navitrak DNA tooling and also injection molds the component parts. The company uses a 55 Shore A, B100 grade of AES’ Santoprene 8000 Series for the soft-touch grips and watertight seal. The 8000 Series of elastomers does not require drying and provides superior colorability, a critical property for consumer goods.

“Meeting the complex seal-off requirements of the overmolded part was a challenge,” says Dave Ricker, system engineer, Navitrak. “With input from Protoplast we designed the Navitrak DNA using a state-of-the-art 3D CAD solid modeler. This permitted complex loft shapes to be realized in the model and the mold tooling.”

Not Sprox, Inc. recently changed the design of its Soundog wireless tabletop audio systems using Bayer Polymer’s Makrolon polycarbonate resin coupled with a new coloring technology. The wireless technology allows restaurant and bar patrons to select and listen to any of the establishments programmed TVs. The Soundog system housing is now made of Bayer’s clear or white Makrolon enhanced with Bayer’s proprietary Fantasia Aura color infusion technology.

Aura technology infuses the surface of the already-molded Soundog housing with color. The infusion takes place in a heated bath containing a dispersion of dye and a proprietary surfactant. The coloring, which takes from two to three minutes, is fully integrated into the part and will not rub off. The coloring technology is ideal for low-volume parts and eliminates the costs associated with using pre-colored resins.