As electronic products get smaller, faster, stronger, and cheaper, can engineering thermoplastics keep up? The engineers at GE Advanced Materials (Pittsfield, MA) have been hard at work to make sure their materials keep pace. The company this month introduced host of new plastics aimed at demanding electrical and electronic applications. Here's a closer look at them:
PEI flexes its muscles in circuitry. As a lower cost alternative to polyimide in flex circuitry applications, GE has developed a trio of polyetherimide (PEI) films that combine thermal and electrical performance with chemical resistance, adhesion to metals, heat-seal capabilities, and good tear strength. ULTEM EXSP0023 has the best heat performance of the three with a glass-transition (Tg) temperature of 245 C. It also has a dielectric strength of 4,700 volts/mil and a dielectric constant of 2.9 at 10 GHz. Next in line is ULTEM 500B film, which has a Tg of 225 C and a dielectric strength of 5,300 volts/mil, and a dielectric constant of 3.3. ULTEM 1000B has a Tg of 217 C and electrical properties slightly above those of the 500 B. Aside from flex circuitry, applications for the new films include bar code labels, flexible heaters, stiffeners, insulative tapes, motor insulations, speaker cones, and wire wrapping. These films can also be thermoformed into a variety of products. All three products are available in thicknesses from 2 to 28 mils and in widths up to 48 inches, the films
Polycarbonate stays toughs in the cold. For electronics enclosures needing good low-temperature impact performance, GE added two new grades to its LEXAN EXL polycarbonate-siloxane copolymer. The siloxane lends some improvements to the cold temperature impact, allowing the material to remain ductile down to -80 C. One of the new grades, LEXAN EXL 9112, has the best flow properties of any flame resistant (UL 94-5VA) polycarbonate-based material in GE's portfolio, making it a good fit for thin-wall electronics enclosures. The other new grade, ELX 1434, has been formulated to endure long-term UV exposure. It targets stationary outdoor electronics and portable devices that see lots of sunlight.
Get the lead out. Two new THERMOCOMP glass-reinforced composites from LNP Engineering Plastics, a GE Advanced Materials Company, have been formulated to stand up to thermal demands of lead-free soldering methods, such as infrared reflow soldering. One new grade, HT Solder UF-1006, is based on polyphthalamide (PPA). The other, HT Solder ZF-1006, employs a matrix of modified polyphenylene ether (PPE). Both grades have a 30 percent glass filling, offer heat distortion temperatures in excess of 260 C, and feature a halogen-free eco-compliant flame retardant package. They also have mold shrinkage values similar to those of the polyester materials, possibly allowing them to serve as a drop-in replacement for incumbent materials.
Wired plastic. Usually DC cords and plugs use vinyl, thermoplastic urethanes (TPU), or flame-retardant polyethylene (PE) as their wire-coating material. GE has come up with an alternative to these materials in the form of modified polyphenylene ether (PPE) resins. Unlike vinyl, these new modified PPE grades contain no halogens. And they offer a lower specific gravity than TPUs or flame retardant PE, potentially reducing the weight reductions. Two new grades are currently available, both of which have passed OEM bending-strength tests. NORYL WCD910has been developed for use in DC cords, and NORYL WCP has been formulated for use in plugs.
New ULTEM films could serve as an alternative to polyimide films in
flexible circuitry applications.
Film viewing. For LCD diffusers, GE has developed a film that uses an optical quality polycarbonate with built-in diffusion properties to take the place of polyester films that get their optical properties from coatings. These ILLUMINEX films get their optical properties from two proprietary technologies. The first uses additives to incorporate diffusion properties into the resin itself. The second involves a surface modification to the films as part of the melt-calendaring process. This texturing process creates a "random surface profile" that helps distribute light evenly, one of the primary functions of diffuser films.
For more information on these new materials from GE Advanced Materials, go to www.geplastics.com
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LEXAN EXL, a polycarbonate-siloxane copolymer, has been formulated to bring
some cold-temperature impact performance to electronics components, like this cell phone battery.