Water-borne PUD adhesives with bio-based polyol component

From a purely technical point of view, they could replace conventional adhesives in wood, furniture and automotive applications without major modifications. Solvent-free, water-borne polyurethane dispersions (PUD) are used as adhesives in many products. They consist of a urethane and a polyester polyol component.

In the project, the researchers succeeded in producing the polyester polyols on the basis of renewable raw materials: Succinic acid, sebacic acid, 1,3-propanediol and 1,4-butanediol were suitable monomers. The PUD adhesives produced in this way had a total biogenic carbon content of over 50 percent and had technical characteristics close to the market standard in the wood, furniture and automotive application areas. However, biobased shoe adhesives still need to be optimised.

Reduced CO₂ footprint

Within the framework of the cooperation project, it was even possible to demonstrate bio-based production up to production scale using the example of a polyester. “The only obstacle to commercial implementation is the cost of raw materials. They are currently even higher for bio-based chemicals than for their fossil counterparts. In the medium term, however, these prices may converge,” explains project leader Dr. Martin Melchiors from Covestro.

Then there would be good market opportunities, because the bio-adhesives also have advantages in terms of climate protection, as a calculation by the Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT) shows: According to this, bio-based PUDs have a CO₂ footprint reduced by more than 25 percent compared to conventional fossil-based PUDs.

You can find more information on the website of Fachagentur Nachwachsende Rohstoffe.

Save the date:

European Coatings will host its second conference on biobased coatings and coatings raw materials on 23 October 2019.

Image source: Pixabay