Blending efficiency in the manufacture of particleboard
Given the research and findings from the chipout study at particleboard plants at Gympie and Benalla a study was extended to look at resin efficiency in particleboard overall.
The existing method of determining resin efficiency is the Kheldale test i.e. the presence of nitrogen in amino resins. This is a very crude test and does not discriminate between large and small flake.
It is just an overall average of resin content. AWT developed a new resin content test stratified by flake size and this showed a large degree of variability in the amount of resin on larger flake, which imparts bending strength to board.
By far the largest amount of resin ends up in the smallest sized flake fraction which imparts very little bending strength to the board.
The amount and variability of resin on flake after blending will dramatically affect the properties of particleboard and in particular the amount of resin required and the overall density of the panel.
All particleboard blenders destroy flake and in so doing reduce the potential bending strength of the panel.
With the addition of a multi phase wetting system Rezex A, manufactured by Oxford Technologies, AWT has developed a technique to improve the effectiveness of particleboard blenders including new generation PAL blenders by improving resin coverage, reducing variation in resin coverage as well as significantly reducing the damage to flake caused by blending.
This can result in significantly improved physical properties, leading to the reduction of particleboard resin loadings and/or reduction in particleboard density and a significant reduction of dust and glue spots.
This can be achieved with no capital expenditure i.e. no requirement for new style blenders.
The following references are the result of trials of many particleboard plants around the world.
References -