ompounding technology has been used to develop a heat-resistant polycarbonate (PC) material that was selected for use in the panorama roof of Toyota's Prius α. The roof was molded by Toyota Industries Corp. (Aichi, Japan) and is reportedly the world's largest.

The weight-saving plastic roof was molded from a PC grade supplied by Mitsubishi Engineering-Plastics (MEP, Tokyo). Superior hard coat adhesion is another feature of the grade. A reinforced PC alloy material for the window frame also featuring improved retention of heat stability was also developed jointly with Toyota Industries.

MEP's recent developmental efforts in the PC field do not stop there. High hardness, high transparency PC resin grades have also been realized through compounding technology. Standard PC grades feature a pencil hardness of 2B, with hard coating normally employed to improve surface hardness. MEP has improved on this hardness, realizing 2H in a new extrusion grade, while at the same time retaining the inherent properties of PC such as optical clarity, flame retardance and processability.

MEP has also debuted two injection grades with high hardness that utilize non-brominated flame retardants. They are rated at UL94 V-0 at thicknesses of 1.2 mm (H pencil hardness) and 1.5 mm (F pencil hardness), respectively. All of these new grades boast total light transmittance of 87% and haze of less than 1%.

MEP is targeting the electrical and electronics sector for these new grades in component, film and sheet applications. It sees particular opportunities in applications currently using hard coats, such as covers and touch panels. -[email protected]