Increased illuminance and energy saving simultaneously achieved by highly functional reflectors

Furukawa Electric’s foaming technologies originated in the early 1960s, when our foamed polystyrene began to spread around the world. The trigger for our cable sheath reforming technologies was the launch of polyethylene foaming development at our Central R&D Laboratory utilizing our unique polyethylene resin chemical cross-link technologies. Then in 1964 we released FOAM ACE, a chemical cross-linked foamed polyethylene. Later, in 1984, we produced FUNEN ACE, inorganic, highly packed foam and approved flame-retardant for use in folded-plate roofs. In the same year we developed EFCELL, non-cross-linked extruded PP foam, and our own foaming technologies, with which we have supplied the world with a range of unique foamed plastic products.

Another product evolved from these foaming technologies is MCPET, microscopic PET foam that we successfully developed in 1997. Focusing on improving the material’s mechanical properties by reducing the size of its bubbles to less than 10µm, repeated resin selection and trial and error of different technologies resulted in the achievement of the world’s first microcellular formed PET resin. Initially, we tried to expand sales of MCPET in the food tray field but failed to demonstrate the absolute superiority of the material’s features. But, through exhibitions and publicity activities in various media such as clients’ in-house newsletters, we did discover a function of light reflecting performance not seen in existing foamed plastic products.

Looking at the light reflecting performance of MCPET, it has very high total reflectance and diffuse reflectance, more than 99% and 96% that of barium sulfate respectively. Its light diffusion capability is also highly rated, and it is adopted in internally illuminated signboards and lighting equipment for the purpose of reducing the number of light sources and improving unevenness. It also has a track record of being used by many manufacturers as a backlight reflector in LCD televisions.

Even after the success of MCPET, Furukawa Electric has not paused in its development work. In pursuing a fundamental reflection mechanism, we have become able to reduce the size of bubbles to 1µm. At present, we have achieved both total reflectance and diffuse reflectance of more than 100%. In 2013, we also launched MCPOLYCA, microcellular foamed polycarbonate resin with applications in many materials. It is being adopted especially in the lighting field due to its high molding processability.

The merits of the two MC Series products, MCPET and MCPOLYCA, are increased illuminance and energy conservation in lighting. With their high reflectance, they enable the number of LED modules to be reduced while increasing luminance. When used in internally illuminated signboards, there are cases of average luminance increasing by around 1.6 times even though the number of light sources is reduced by about a third, and when installed alongside inverters in lighting renewal, they can reduce electricity usage by more than 50%. They have performed well as power saving products during power shortages in the immediate aftermath of earthquakes.

Recently, more and more people have been switching to LED lights for the purpose of saving energy, but the problem is that LEDs are strongly directional and emit a narrow angle of light. To deal with this problem, Furukawa Electric is taking advantage of the high reflectance, stiffness and moldability of MCPET. We are proposing a new “indirect design” that will resolve the issues in LED lighting. This is a mechanism for diffusing the light from an LED using a 3D shape made of MCPET and having as much of the light as possible hit it. As well as improving the transmittance of the diffuser that impedes light efficiency, MCPET has the merit of thinner and lighter.

In recent years, MCPET has also been adopted as the core material of the diaphragm in the speakers of smartphones and tablets, utilizing its lightweight and hard characteristics. It has also begun to be used for the diaphragm membranes of earphones and headphones due to its excellent acoustic characteristics. Going forward, the scope of use of MC Series products is expected to expand further into new fields.