An incidental discovery in a wood products lab at Oregon State University (OSU) has produced a new pressure-sensitive adhesive.
The researchers who developed it believe that it may revolutionise the tape industry since it is an environmentally benign product that works very well and costs less than existing adhesives based on petrochemicals.
The new adhesive can be produced from a range of vegetable oils and may find applications in duct tape, packaging tape, stick-on notes, labels, even postage stamps – almost any type of product requiring a pressure-sensitive adhesive.
The discovery was made essentially by accident while OSU scientists were looking for something that could be used in a wood-based composite product – an application that would require the adhesive to be solid at room temperature and melt at elevated temperatures. For that, the new product was a failure.
’We were working toward a hot-melt composite adhesive that was based on inexpensive and environmentally friendly vegetable oils. But what we were coming up with was no good for that purpose, it wouldn’t work,’ said Kaichang Li, a professor of wood science and engineering in the OSU College of Forestry.
’Then I noticed that at one stage of our process this compound was a very sticky resin,’ Li said. ’I told my postdoctoral research associate, Anlong Li, to stop right there. We put some on a piece of paper, pressed it together and it stuck very well, a strong adhesive.’
Shifting gears, the two researchers then worked to develop a pressure-sensitive adhesive, the type used on many forms of tape, labels and notepads.
’This adhesive is incredibly simple to make, doesn’t use any organic solvents or toxic chemicals and is based on vegetable oils that would be completely renewable, not petrochemicals. It should be about half the cost of existing technologies and appears to work just as well,’ Li said.
There have been previous attempts to make pressure-sensitive adhesives from vegetable oils, Li said, but they used the same type of polymerisation chemistry as the acrylate-based petrochemicals now used to make tape. They did not cost much less or perform as well, he added.
The new approach used at OSU is based on a different type of polymerisation process and produces pressure-sensitive adhesives that could be made from renewable crops such as soy beans, corn or canola oil, instead of petroleum-based polymers.
The technology should also be fairly easy to scale-up and commercialise, Li said.
’OSU has applied for a patent on this technology and we’re looking right now for the appropriate development and commercialisation partner,’ said Denis Sather, licensing associate with the OSU Office of Technology Transfer.