Jon Excell visited TWI to find out about biodigestible circuit boards.
Everyone knows how quickly the value of electrical goods depreciates. You can buy a home computer today for £2000, and by the time you’ve finished paying for it, it’s worth less than the desk it’s standing on.
However, despite the plummeting life span of electrical products, recycling is still not a particularly viable option. It’s usually far cheaper to just throw away old PCs, laptops and mobile phones rather than embark on the laborious process of rescuing anything which is still useful. Take printed circuit boards for example.
Currently, recycling involves blowing hot air onto the board to melt the solder and then employing vacuum suction to remove integrated circuits (ICs). Using this process, only around 3 to 4 ICs can be removed per minute. The board is then usually incinerated or buried in a landfill site. Both options are environmentally hazardous.
Imagine, though, that the circuit board is made from uncooked lasagne. When the assembly reaches the end of its life it is dropped it into a pan of boiling water. The pasta’s strength properties are denuded in seconds and the reusable parts can be detached with a minimum of effort. Finally, to complete the recycling process, why not cook up a sauce and have your old workstation for lunch – how about Olivetti Carbonara?
Of course, Pasta is not a serious substitute, but it illustrates perfectly the concept at the heart of a collaborative project, led by Dr Roger Wise, between TWI and BTTG (British Textile Technology Group) aimed at designing a biodigestible circuit board.
The project is driven by many factors: the massive share in the electronics market of `short-life’ products, the desire to reduce disassembly costs, and, perhaps most importantly, the impending Waste Electrical & Electronic Equipment Directive. This EU legislation, due to come into force in 2004, will require OEMs to take back equipment after its working life and prohibit the use of lead solder.
The fundamental idea behind the collaboration is not new. According to Dr Dosten Baluch, the chemist in charge of business development for the project, both IBM and Fujitsu were looking into this technology back in the early `90s. IBM considered the use of lignin to make circuit boards, and even filed a patent, but since then the project seems to have been abandoned. The reason for this? Baluch speculates that lignin is not viable, and is reasonably confident that neither company is going to beat him to it. `I guess if they’d been following this up, they’d have something by now.’
TWI’s project also focuses on the use of natural products. chitin (obtained from shellfish), gelatin, and plant extensins – proteins produced when the body of a plant is damaged – are all candidate materials. All exhibit many of the physical properties which are important for a circuit board, and all are being tested and chemically modified to either equal or surpass the thermal, electrical and mechanical performance of the glass fibre reinforced epoxy laminate benchmark. Flammability is also a big issue, and one significant disadvantage of epoxy-laminates is that they require the use of halogen flame retardents which are also likely to be outlawed by the directive. (see p7)
The properties of these `natural’ materials are tailored by the addition of polymers, plasticisers, fillers and other additives, but, because of the commercially sensitive stage of the project, Dr Baluch was unwilling to go into any specifics. What matters most about this technology is that very little is wasted; the circuit board material will be reconstituted, and the small integrated circuits from the boards have an almost unlimited life span. Indeed, says Baluch, it’s anticipated that in 5 or 6 years time 50% of the value will be in these integrated circuits’. Another important aspect of the research is the development of an efficient and controllable biodegradation process. After all, large electronic OEMs are not going to embrace a technology which means that products are going to start decomposing the second they’re taken out of the box. Indeed, this has been one of the main challenges in the design of electronic housings made from biodigestible material.
Exposure to the environment makes it harder to guarantee stability. However, a protective coating will not, says Baluch, significantly alter the speed at which the material is `digested’.
However, it’s important to note that this technology is not designed to sit unused for years but aimed at the mass produced, low life-cycle electronics market. Dr Baluch backs this up with reports which forecast that by 2003 computer hardware and communications equipment will account for 65% of the industry’s production. A staggering figure considering that this appears to be the only initiative dealing with legislation which will affect everyone.
As well as looking into creating a spin-off company, discussions are underway with a number of electronics OEMs who have apparently all expressed an interest in setting up collaborative arrangements.
However, it must be reiterated that the initiative is still in its early stages; the final product is not expected to be around until 2004 and patent arrangements will not be finalised until February 2000.
Inevitably, this technology will not be restricted to circuit boards but will, in Dr Baluch’s words, `present a wonderful window of opportunity for innovation in all manner of applications’. Who knows, one day we may all be driving around in biodigestible cars.
TWI Tel: 01223 891162