COMMENTARY

From Waste to High Value Product: Eco-Hybrid Coating (EHC) as Sustainable Material

By Nano and Advanced Materials Institute (NAMI)


Woodplastic composite (WPC) product is one of the common materials extensively used in construction industry, from plain road pavement to beautiful interior decoration. Their component’s natural behaved very differently. Wood is hydrophilic that would easily absorb moisture or water from the environment and swell to change in shapeon the other hand, plastic is hydrophobic that repel moisture or water.

The water absorption properties by wood causes  poor weather resistance of WPC product that it would deform easily under atmospheric changes. In addition, due to the stubborn and restricted process of existing WPC production limits the product customization, especially the shape of final product, which limits the application flexibility of WPC.

Realizing the limitations of existing WPC products, a Hong Kong company who has experience on applying foreign WPC products approached Nano and Advanced Materials Institute Limited (NAMI) with an Innovation and Technology Fund of HKSAR-supported R&D project to develop a novel Eco-Hybrid Coating (EHC).

THE COATING SOLUTION DEVELOPMENT

EHC is a solution form coating to be applied on metal surface to provide WPC-like appearance. It is made from recycled wood and plastic wastes. By the NAMI’s innovative formulation technology, the hydrophilicity of recycled wood is reduced and the affinity between plastic and wood are increased, enhancing their compatibility to prevent deformation by weather change.

The EHC is fabricated as solution form coating by properly mixing process with NAMI’s synthesized water-based resin. The solution form EHC can be easily applied to metal substrate by simple brushing or spraying processes, opening the application on different shapes and forms of product. Furthermore, EHC is possible to be cured at room temperature, making on-site application possible.

THE DEVELOPMENT PROCESS

The developed EHC not only solves the existing limitations of WPC, but also has a remarkable environmental advantage of recycling waste wood and plastic without sorting requirement. Mixed sources of common plastic wastes, such as PET, HDPE, LDPE, PP, PS, etc., and wood wastes can be used directly to produce EHC. It is estimated that 3,154 tons of wood waste and 2,343 tons of plastic waste are being produced in the Hong Kong each day, these wastes can be used to produce EHC locally and reduce the pressure of landfill in Hong Kong.

The trial production for the developed EHC is ongoing in Hong Kong and product launch is expected soon. Due to the good weather resistance and high application flexibility, EHC product are suitable for both indoor and outdoor applications, such as theatre, office, pavilion, gallery, etc., to be installed as louver, wall, fence, etc.

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