Optical clarity, durability, and impact resistance make Lexan polycarbonate a popular choice for demanding automotive applications like forward lighting.
In mold decoration using Lexan film and Visualfx special-effect resins and films is a durable means of adding graphics and striking colors to the surface of telecommunication devices and business machines.
The high heat resistance and dimensional stability of Ultem HPP lets designers replace metal in motorcycle and automotive headlight reflectors.
Cytra resins are ABS/PC/PBT polymer alloys that compete with engineered thermoplastics and polypropylenes for unpainted automotive interior cladding and trim applications.
Lexan polycarbonate may have been around for over 50 years, but it, along with other resins and color effects from GE Plastics, Pittsfield, Mass. (www.lexan.com), sport new chemistries and processing techniques that have bolstered their use in an expanding array of demanding applications. Here's a preview of the most recent innovations for the various resin systems, which will be featured at NPE 2003:
Lexan polycarbonate. Lexan SLX Film is a high gloss and colorfast polycarbonate (PC) that was developed as an automotive paint replacement. It is back molded with Lexan or Xenoy resins using common in-mold decoration techniques and reportedly is the only material that combines 10-yr gloss retention with chemical and scratch resistance. According to Richard Crosby, global product manager for Lexan, "SLX film is ideal for large automotive parts and eliminates painting and its associated volatile emissions. And scratches in the SLX film can be buffed using rubbing compounds like 3M Perfect-It." The technology still needs industrialization, so designers of large automotive parts should work with GE's PPDC (Polymer Processing Development Center) during early development. At www.geimd.com, designers can find information on both Lexan SLX films and in-mold decoration.
An injection-moldable version of Lexan SLX reportedly has the color stability of acrylic and impact resistance of PC. Target applications include lighting (refractors, industrial lenses, and cover guards) and automotive (traffic management, emergency lighting, and bug guards).
Lexan EXL is a next-generation PC that is copolymerized with silicone to give it better impact, toughness, and UV weatherability over standard PC," says Crosby. It also has good release properties and is easier to process --10 to 20% better flow and 10 to 40% reduced cycle times. It also exhibits low-temperature impact strength and cold-temperature ductility to -40°C.
Lexan OQ resins have recently been used to create limited-play DVDs. All DVDs are optically read via a laser beam. The beam focuses through the disc surface to an information layer and gets reflected back to the DVD player's photo detectors. Because DVDs are optically read, clarity and transmission of light through disc surfaces are critical to playback fidelity. Flexplay DVDs from New York based Flexplay Technologies Inc., (www.flexplay.com), use proprietary processing to make Lexan OQ-based DVDs unreadable after a predetermined time period lapses.
Lexan can also be fashioned into resistant Lexan Anti-fog Sheets, self-cleaning Thermoclear sheets, security laminates (OQ Sheets) that reportedly have maximum optical clarity, and hard-coated, antifog HPAF Films.
Color special effects. Lexan Visualfx also expands its color options. According to Global Aesthetics Leader Andrew Day, "The 2003 effects add depth or texture using a variety of black and white pigment combinations. These combinations are much subtler than previous color effects, you have to get up close and personal to see the way the pigments interact with light." Options range from rich and glossy Raven (piano key black) to a bold crisp Alpine White. Other hues in the fx palette include Dark Sparkle, Dark Marble, White Sparkle, White Stone, Ferrite, Tempulse, and luminescent.
Visualfx resins are also available in thin films for in-mold decoration. Visualfx films include Diamond, Pearlescent, Illuminate Yellow, Intrigue, and Ares.
High-performance polymers (HPPs). Ultem HPPs are amorphous polyetherimides (PEIs), which are known for dimensional stability and low ionic properties. "Ultem 1010M has improved surface appearance and better heat management," reports Global General Manager of High Performance Polymers, Tim Rash. "It is a recyclable alternative to bulk-molding compounds (BMCs) in automotive applications. And has better optics and moldability than competing thermoset resins."
A high-flow HPP, Ultem ATX200, reportedly has three times the flow at lower molding temperatures than current ATX resins. "This equates to faster molding cycles and thinner-walled parts," says Rash.
Another HPP offering, Ultem XH6050, is based on a new polymeric molecule. "It's the most heat-resistant amorphous resin available for injection molding," claims Rash. Its glass-transition temperature (Tg) is 249°C, letting it compete against metal. "It offers cost advantages over high-temperature resins such as liquid-crystal polymers (LCDs), polyimides (PIs), and polyamide-imides (PAIs)," he continues. "It will serve as a building block for even higher heat-resistant polymers and is a drop-in replacement for previous Ultem products."
A low ionic HPP, Ultem 1010X, provides fire-retardant protection and isolation. It has low particle generation and outgassing which makes it a suitable resin for semiconductor handling applications. Other Ultem resins include high-temperature (GF ATX), an easier to process version (Ultem 1000E), and Superlite composites.
Engineered styrenic resins (ESRs). Cytra resins are ABS/PC/PBT polymer alloys that compete with engineered thermoplastics and polypropylenes for unpainted automotive interior cladding and trim applications. Three new versions are in various stages of development, says Global Manager of ESR Joseph Bleull. Cytra XCT200 is a low-gloss, high-impact alloy with medium heat resistance (75°C). It is slated for automotive applications "below the belt", i.e., where the sun doesn't shine. Cytra XCT300 is a low-gloss, high-impact resin, but withstands higher heat (110°C). Another glass-filled, medium-heat (75°C) version, Cytra XCT500, is in development.