Honda Lock’s door handle. Click to enlarge.

This new film is made with PLANEXT SN4600, an improved grade of Teijin’s PLANEXT bioplastic. PLANEXT is an eco-friendly bio-polycarbonate made with bio-content based on isosorbide from corn-starch and other plants. In addition to excellent moldability and durability, it is superior to oil-derived polycarbonates in terms of surface hardness (pencil hardness rank: H), weather and chemical resistance, and light transmittance.

In addition to original PLANEXT properties such as chemical resistance, transparency and surface hardness, polymer reforming is used to give PLANEXT SN4600 important new properties including gasoline resistance, formability, UV resistance.

Teijin’s gasoline-resistant film is ideal for vehicle doors, which of course have the possibility of coming into contact with gasoline. Optimized heat resistance and filming technology enable high formability for fashioning into complicated shapes. UV protection helps to shield the base material and prevent discoloration.

Vehicle door handles are increasingly being integrated with secure smart-entry systems that enable doors to be locked and unlocked by simply placing one’s hand on a handle sensor. The material surrounding the sensor, however, must be nonconductive to avoid sensor malfunctions, so conventional door handles made of electroconductive chrome plating coated on a resin base are not suitable.

Plastic films made with a metal-evaporation process are nonconductive and already being used as metal substitutes for automotive exteriors, but they are not suitable for door handles because they are neither gasoline-resistant nor highly formable.