How Natural Fibres Can Be Used to Produce Electrically and Mechanically Stable PCBs

(Photograph: NewsOnAIR)

The use of natural fibres in the composite industry is historically a contentious subject, raising questions surrounding just how a combination of bio-based materials and thermoset polymers can be dealt with at their end of life. Could this be a simple box-ticking exercise by companies to decrease their carbon footprint whilst ignoring the waste stream?

Jiva is continuing to develop materials for applications where fibres such as jute can offer some distinct advantages over the market incumbent fibreglass PCB substrates. These advantages include a lower density with subsequently reduced freight carbon emissions, as well as being fully recyclable via Jiva’s novel water-based recycling process. Internal testing also suggests that Soluboard is comparable electrically to fibreglass PCB substrates.

Aside from the improved carbon footprint and recyclability of Jiva’s Soluboard, it is the aesthetic of the material that really makes it stand out from the existing printed circuit board substrate market. Most of the market leading rigid substrates used for single and double-sided applications traditionally comprise of glass fibres and epoxy resin, resulting in a yellow appearance prior to PCB fabrication and the application of the typically green-coloured soldermask.

Jiva’s target is to remove the glass-fibre PCBs from e-waste – the fastest growing waste stream in the world. Whilst the incumbent glass fibres result in negative impacts on the environment due to their inability to be recycled, they are a crucial component of PCB substrates such as FR-4 due to their mechanical strength.

Jiva’s Soluboard is effectively a fibre-reinforced polymer (FRP) in sheet form; as with any composite or FRP, the fibres play a functional role. However, Jiva’s mission of commercialising the world’s first fully recyclable PCB substrate is only achievable by switching out glass fibres for less environmentally impactful alternatives with smaller carbon footprints. Jute is a prime example, already being used to produce hessian or burlap textiles.

Developments have been significant throughout the past couple of decades in the now robust natural fibre supply chain. Jute is second only to cotton in the amount produced and variety of uses, typically grown in South Asia and reaching its full maturity in 4-6 months. Roughly 95% of world jute is grown in India and Bangladesh, then being exported to Pakistan for processing.

The market demand for natural fibre blends is increasing, with jute increasingly being blended with cotton in order to produce ‘juco’. When woven, the tighter weave of calico (cotton) is combined with the hard-wearing durability of hessian (jute). Predominantly a rain-fed crop with little need for fertiliser or pesticides, seasonal yields of approximately two tonnes can be harvested per hectare. (Source: United Nations FAO)

Current jute production levels would provide a more than substantial raw material supply for Jiva’s Soluboard production. One supplementary benefit is also that one hectare of jute crops would consume 15 tonnes of carbon dioxide and release 11 tonnes of oxygen prior to harvest. (Source: United Nations FAO)

Whilst it is Jiva’s intention for Soluboard PCBs to be collected into a concentrated waste stream in order to be recycled via our water-based recycling process, it is also worth noting that jute does not generate toxic gases when incinerated. Shredding and incineration is the industry standard method of recycling, so if a Soluboard PCB was to be processed in this way it would produce significantly lower dioxin levels than existing glass-fibre PCBs.

Jiva is actively searching for partners and suppliers to develop our South Asian jute supply chain. From jute fibre cultivation and sourcing to bespoke textile weaving, we are keen to further our knowledge and connections in order to achieve the highest level Soluboard integration into the PCB industry possible. If you believe you can contribute to our journey, please do not hesitate to reach out at [email protected].