Clear polycarbonate offers higher performance and easier processing

Paul Boughton

Sabic Innovative Plastics is launching a new copolymer technology, known as Lexan HFD specialty copolymer resins. This gives customers high melt flow without traditional decreases in toughness, as well as improved ductility without impacting melt flow.

These materials build upon the clarity, toughness and high performance for which Lexan polycarbonate (PC) resin is known. The new materials are said to open the door to new design options, especially in key application areas where thin-wall parts, complex geometries and high-impact products are required to withstand very low temperatures with no compromise on clarity.
 
Bala Ambravaneswaran, global product marketing director for Lexan copolymer resins at Sabic Innovative Plastics, comments: "Our new Lexan HFD copolymer resins represent a major breakthrough in expanding the capabilities of the Lexan resin PC molecule to meet critical, highly specific customer needs; especially greater design flexibility, extreme top-end performance and outstanding surface aesthetics. We have again raised the bar in advanced thermoplastic innovation and will continue to push the boundaries of our PC technology to help our customers win in the markets they serve."
 
Based on proprietary polymer chemistry, Lexan HFD copolymer resins are part of an expanding portfolio of six innovative, specially engineered copolymer materials with extreme performance capabilities. By reducing moulded-in stresses, improving low-temperature impact and delivering excellent surface aesthetics, these materials enable new, differentiated designs to stand out from the competition.
 
Drawing on its extensive technological expertise, Sabic Innovative Plastics created this new polymer chemistry that combines two different monomers to ensure high performance in demanding applications. To support its goals of creating sustainable materials, up to five per cent bio content has been incorporated into this new copolymer. Lexan HFD copolymer resins are available in five grades, with or without UV stabilisers. Additionally, the company is developing glass-filled grades with and without flame retardancy, food contact grades, blends incorporating other Sabic Innovative Plastics' resins, and super-high-flow grades.
 
Lexan HFD copolymer resins are engineered to provide up to 40 per cent higher flow at the molecular weight than standard Lexan resin, thereby preserving desirable mechanical properties. Higher flow helps customers create thinner-walled parts - such as appliance and device housings - without the risk of cracking upon removal from the mould. It also reduces moulded-in stresses to avoid birefringence (the 'rainbow' effect) in optical applications such as camera lens housings, and to enable designs to be moulded with sharp notches and corners without fear of breakage. High flow also permits faster processing speeds for higher productivity.
 
From an aesthetic standpoint, higher flow solves the issues often experienced with glass-filled materials: Lexan HFD copolymers flow around and hide the fibres, thereby producing surface gloss that is 30-40 per cent higher compared to a standard glass-filled PC. At the same time, the materials provide high ductility at colder temperatures (down to -40degC) compared to standard PC, which can become brittle. Clarity is also maintained at these temperatures. These attributes make Lexan HFD copolymer resins suitable for military eyewear, windscreens and face shields.
 
Lexan HFD copolymer resins process at a temperature about 20 degrees lower than standard PC with the same ductility. This property allows heat-sensitive additives to be used without impacting their performance. In addition, the lower processing temperature delivers advantages to in-mould decoration and two-shot overmoulding applications.
 
For more information, visit www.sabic-ip.com