German Institute Partners with Henkel to Develop New Adhesive

In the BIOVIN project, the Leibniz Institute for Catalysis Research (LIKAT) and Henkel have worked together to develop an innovative bio-based adhesive whose production is based on the desticking technology of carbohydrates and vegetable oils. This breakthrough means that in the future, when producing electronic products or household appliances, this new adhesive can be used to improve the repair convenience and recyclability of products. For example, with this reversible combination, when the device fails or needs to be upgraded, the parts can be easily removed without having to destroy the entire device, greatly simplifying the repair process and reducing the generation of e-waste.

During the course of the study, the researchers also unexpectedly obtained other interesting secondary results, in particular their successful development of a new, highly selective catalytic process for the production of divinyl ether (DVE). This result is not only significant for the BIOVIN project itself, but also opens up new possibilities for other applications in the chemical industry. The project is funded by the German Federal Ministry for Food and Agriculture (BMEL) and managed through the project management organization Fachagentur Nachwachsende Rohstoffe e.V. (FNR).

In the Biovin project, researchers have succeeded in producing new polyols at high yields and low cost, starting from commercially available bio-based platform chemicals. To test the performance of these intermediate products, the researchers took two different approaches. First, they tested polyols as reactive components in polyurethane adhesives. The experimental results show that the properties and key data of the obtained polyester polyols are very similar to those of similar petrochemical polyols, which indicates that bio-based polyols can completely replace traditional petrochemical products in performance.

On the other hand, the researchers processed the polyol into a new bio-based multifunctional divinyl ether (DVE). To this end, LIKAT has developed a catalytic synthesis method that can convert almost any biobased polyol or phenol into vinyl ethers. Compared with the most mainstream commercial processes to date, this new process has a yield of up to 98%, significantly reduced the formation of unwanted by-products, and is more selective, efficient and environmentally friendly. Nevertheless, the search for efficient and cost-effective catalysts remains the focus of future research.

Using vinyl ethers, researchers have prepared new adhesive formulations that could be alternatives to commercially successful acrylic ester systems. The study found that these new adhesives have similar curing behavior to acrylate systems, but exhibit poor adhesion to metals and better adhesion to plastics. Other advantages of these adhesives include lower toxicity, lower odor, and the fact that they are derived from renewable raw materials, which gives them a significant environmental advantage.

In addition, divinyl ether (DVE) provides the basis for adhesives that are specially "degumped" by heat, light or acid. This feature enables the recycling of electronics and household appliances and supports the development of a circular economy. In the Biovin project, the researchers produced a total of 14 different prepolymers using divinyl ether (DVE) and commercially available bio-based dicarboxylic acids. These prepolymers do not require additives or catalysts, and in most cases do not require solvents. It was confirmed by spectroscopic studies that the debonding was achieved by thermal cracking and chemical cracking under mild experimental conditions. Although further optimization is still needed, the developed prepolymers have shown great potential for use in new, recyclable adhesive systems. These research results not only bring a breakthrough to the BIOVIN project, but also provide new ideas and solutions for the entire adhesive industry and related fields.