INVESTIGATION OF RECYCLABILITY OF BIO-BASED COATINGS ON FIBRE BASED SUBSTRATES

Abstract

Coated substrates were made using Ethylene Bis-stearamide wax, Soya protein and Polyvinyl alcohol as coating material on two substrates i.e., CKB Board and Algro Finess paper with coating weight of 15 g/m2 and 10 g/m2 respectively. Filtrate analysis was carried out with the measurements of pH, Conductivity, Chemical oxygen demand and Bio-chemical oxygen demand. The recyclability was investigated by the Harmonised European laboratory test method (CEPI method). Soya protein coated substrates had the maximum value of conductivity which referred to the fact that soya protein was able to enter the filtrate and separate from the fibres quite well which was confirmed by the COD and BOD measurements as it had the second highest COD and highest BOD value. For all the coated substrates, the values of COD and conductivity were found higher than the uncoated substrates which proved the presence of coating materials in the filtrate obtained from the pulp suspension. Algro Finess with the soya protein was found as the most biodegradable sample with the highest value of BOD/COD ratio. According to the sheet adhesion test, the least scores were rated to the polyvinyl alcohol coated substrates stating them as the least recyclable coating. The uncoated CKB Board and Algro Finess paper secured full scores as they had no adhesion effect or sheet damage due to the absence of the coating.