Keyboard seamlessly integrated into the housing

Leverkusen – Sony Ericsson’s W950i Walkman® smart phone boasts a particularly innovative feature: the flat, back-printed keyboard is seamlessly integrated into the phone’s housing. The keyboard and housing of the UMTS phone – which also incorporates a digital music player and a large touchscreen – thus constitute one continuous part. “This not only simplifies assembly and the associated logistical processes, it also means there are no gaps between the keys through which dirt particles can enter,” says Georgios Tziovaras, a FIM expert at Bayer MaterialScience. The concept for the sophisticated new housing design was evolved in close cooperation with SonyEricsson. The two partners finally came up with a design using three materials from Bayer MaterialScience, manufactured with a combination of film insert molding (FIM) and soft/hard technologies.

The first step involves printing, forming and punching a 175-micrometer-thick polycarbonate-polybutylene terephthalate Bayfol® CR film (PC +PBT) to produce a film insert. After this, a rigid frame made of Bayblend® (PC+ABS) is integrally molded on to the film. Then, in a second cavity, the keyboard is back-injected with Desmopan® flexible thermoplastic polyurethane (TPU) to form the additional functional elements of the keyboard and stabilize the film. Bayfol® CR is used because, compared with a straight PC film, for example, it is much more flexible – a property that is important for the reliable functioning of the keyboard. It is also particularly resistant to chemicals and can easily be printed and shaped.

About Bayer MaterialScience:
With 2006 sales of 10.2 billion euros (continuing operations), Bayer MaterialScience is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction and the sports and leisure industries. At the end of 2006, Bayer MaterialScience had 30 production sites and employed approximately 14,900 people around the globe. Bayer MaterialScience is a Bayer Group company.