Thomas Marwedel | June 26, 2018
Our blog post of the week is today a really exciting one! We have been so fortunate to interview Peter Küker, who is a technical manager at Covestro in Germany. Peter has been working with cellulose fibrils in a project at Covestro for some time, and today he is sharing his views and experience on utilizing the fibrils in some of the Covestro formulations for adhesives. Don't miss out on this opportunity to learn more about the actual experience of utilizing the effect from the fibrils on rheology, dispersion and material handling.
Interviewer (Thomas Marwedel, Borregaard):
– Peter, you have incorporated cellulose fibrils (Covestro used Exilva from Borregaard) into a newly developed adhesive formulation. How would you describe cellulose fibrils as a functional additive?
Peter Küker:
– We have obtained very good rheological properties in the adhesive formulations. In particular, the good thixotropic behavior allows us to set high viscosities for spray applications. In addition, the viscosity remains stable over over a broad pH range.
Interviewer (Thomas Marwedel, Borregaard):
– Cellulose fibrils are made from renewable sources. How important is this aspect for finding new raw materials?
Peter Küker:
– It is very important for us at Covestro, not only to produce our raw materials from a renewable source, but also to use additives in our recommended formulations which are also produced from these sources.
Interviewer (Thomas Marwedel, Borregaard):
– Can you give us a few more details about the actual formulation?
Peter Küker:
– It is a starting formulation (CRD 1006 – based on Dispercoll C© dispersions for brush and roller application) with good wet strength particularly suitable for absorbent substrates such as leather, textile or foam bonding.
Interviewer (Thomas Marwedel, Borregaard):
– What is the specific contribution from cellulose fibrils?
Peter Küker:
– Cellulose fibrils is helping us to provide a stable viscosity, which remains constant over a longer storage time. Storage-stable adhesive formulations are very important for our customers, because their adhesives are marketed worldwide.
Interviewer (Thomas Marwedel, Borregaard):
– What in particular should be considered when applying cellulose fibrils?
Peter Küker:
– Cellulose fibrils need high shear forces to make it 100 percent effective in its thickening process. Most adhesive dispersions are sensitive to high shear forces. It can therefore be important to premix cellulose fibrils in a shear stable component.
Interviewer (Thomas Marwedel, Borregaard):
– Since the process you were looking at lacks high shear rates: how did you handle that?
Peter Küker:
– We developed a new product (containing cellulose fibrils) in cooperation with the Borregaard R&D department (which have developed Exilva). We found that it suits also well into polychloroprene dispersions.
Interviewer (Thomas Marwedel, Borregaard):
– What advice would you give people who are using cellulose fibrils for the first time?
Peter Küker:
– First of all, it is important to understand the product in terms of both its physical and chemical properties. Cellulose fibrils impact a formulation in many ways, having an effect on different characteristics, e.g. stability, surface hardness, and reduction of processing costs of the formulation.
Interviewer (Thomas Marwedel, Borregaard):
– Are there further applications you are looking at with Cellulose fibrils?
Peter Küker:
– Cellulose fibrils has become an interesting building block for several projects. You will understand that I cannot give you further details. But due to its multifunctionality and natural origin, it is attractive for future development, also outside the field of adhesives.
The Exilva Blog says a big thank you to Peter for providing your valuable feedback on your experience on cellulose fibrils
