Bio-based adhesives for environmentally friendly package and wood products

New challenges are faced by adhesive manufacturers through increase in the price of petroleum and request of low-emission chemicals. VTT has developed formulations on price-competitive adhesives based on natural and renewable raw materials for environmentally friendly end products, such as formaldehyde free starch based adhesives for gluing of fiber based products and tannin components replacing phenolic gluing wood composites such as chip boards, plywood and fiber boards.

The adhesive formulation is comprised of transglycosylated starch and hydroxyl propylated starch, and the adhesive is hardened using a cross linker. The formaldehyde free adhesive formulation shows similar or better strength properties compared to the commercial resin depending on the compression temperature. The novel tannin glues have the benefit of low viscosity, moisture resistance and tensile load. Bio-based packaging also requires the adhesive to be bio-based. The advantage of the novel hotmelt material is that lower melting products can be achieved and thereby be prepared by simple melting i.e. no extrusion is required. Transglycosylated native starch has also been used in the preparation of aqueous adhesive formulations.