Use of waste powder coatings as binders for the manufacture of composite materials

Powder coatings are 100% solid dry powders that are used to coat a wide variety of substrates. They are considered an environmentally friendly coating option with no volatile emissions and minimal overspray wastage. Fines (5% of the powder manufactured) that are not fit for application are also generated during production. Reworking them into usable powder is a costly and cumbersome process and hence they are not reclaimed. For this study three powder coating thermosetting powders were selected. Composites were made by using waste powder coating powders (WPCP) and fines as a primary binder, along with secondary binders and sawdust as the reinforcing material. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to characterise composite boards formed using compressive moulding. The composite boards resemble particle boards and were tested for their mechanical properties according to the prescribed standard (AS/NZS 1895.1:2004 for Reconstituted Wood Based Panels). All results confirmed that the composite boards had mechanical performances comparable with conventional commercial boards. As they are constructed wholly from industrial waste materials these particle boards are novel products, and commercialization of this industrial ecological product is envisioned.