Ecocoboard - Processing Technology And Quality Standarization
A simple and robust technology has been developed to produce high performance fibreboards from whole coconut husks, without the addition of chemical binders. The technical details of this process as were published in the CFC Technical report nr. 43, CFC/FIGHF/11 are highlighted. Processing conditions, resulting technical properties of the produced boards are shown.
Binderless board production by compression moulding from whole coconut husk requires pre-processing of the husk material for conversion into a homogeneous fibre mat. Methods to open and homogenize the husk material have been studied to select the most suitable technology. Steam explosion, extrusion refining and different milling techniques were applied on whole fresh coconut husks. The effects of the pre-processing technologies on particle size and moisture content were compared in relation to board formation and mechanical properties. The dry milling technology by far gave the best results with respect to homogeneity of the husk material and mechanical properties of the binderless board material produced from it. This method is also favoured when considering the required investment in equipment.
The technical aspects of husk raw material quality (age, variety) on the properties of the produced boards are discussed. Coconut variety did not show an effect on board properties. At increasing maturity of the nuts, board properties improved.
The effects of processing conditions of coconut husk opening and the moisture content of the refined material on final board manufacturing are shown. It was found that for the production of high performance board material the moisture content is critical and should be reduced to below 10%. Too low water content, however, limited the flow of intrinsic cocos husk resin. The pressing hot conditions giving the strongest board material and the best flow of lignin resin in the fibre mat were selected at 180 C and a pressure of 15 MPa (550 kN) during at least 3 minutes. Cooling under pressure was required to avoid warping and blister formation for moisture contents above 3%.
The mechanical properties and water absorption characteristics of the coconut husk boards produced at optimal conditions can compete very well with commercially available boards like MDF, OSB and plywood and they surpass those of particle board and hardboard. The boards can be sawn and drilled like tropical hardwoods. Due to the high density of the boards, pre-drilling was required to screw or nail the boards.
A short overview of the economical aspects of the production of Ecocoboard is presented. The relative contributions of investment costs, raw material costs, production coast (energy, manpower) will be shown below.