It took more than seven years of research and development, but Scion chemist Warren Grigsby reckons his ‘green glue’ will underpin a new generation of environmentally-friendly wood panels.
Manufactured wood panels, such as medium density fibreboard (mdf) and particle board are a ubiquitous part of modern homes and offices.
Traditionally, wood panels have been manufactured using wood fibres held together with a urea-formaldehyde adhesive.
“The background behind these panels,” says Warren, “is that you can get these flat sheets of wood that the tree doesn’t grow.”
For the past few years, Warren has been developing alternative ‘green’ resins and adhesives.
“The technology we’ve developed here is a 100 percent bio-based – all the components grow on a tree or plant.”
The main component of Warren’s adhesive is lignin, which he says “holds the wood fibres together” in a tree.
The brown lignin he uses in his recipe is extracted from a black liquor, that is a by-product of pulp and paper manufacture.
Warren says that in New Zealand at the moment the black liquor is burnt at the pulp and paper mill to provide energy, but he would like to harvest it and add value by converting it into a resin-based adhesive.
The lignin is combined with other protein and starch ingredients sourced from cereal flours and cattle feed.
“The trick,” says Warren, “is for us is to bring these three ingredients together in a way that is very simple to manufacture.”
“We’re using very complicated chemistry in a very simple way to deliver the components of that adhesive to the wood fibre to stick the wood fibres together.”
Business development manager Rob Lei says that this green bioadhesive will serve a growing trend of “moving away from fossil-derived materials in the built environment.”
The new adhesive has a number of advantages – it is very low in formaldehyde, and because the resulting wood product is entirely bio-based the wood panel can be completely recycled or even composted at the end of its life.
It can also be used without changing existing production lines and systems.
As part of trialling the adhesive, Scion worked with wood panel manufacturers to produce industrial quantities wood sheets in their factories, which Rob says was nerve-wracking for everyone concerned.
“I think it’s very easy for science to stay at the lab bench and be comfortable there,” he says.
“And this is really the job of Scion and our researchers - to make an impact and take things to scale. And that’s scary.”