Every year, we are reminded at earlier and earlier dates that our planet’s resources are finite, and we are using them up at an increasingly fast rate. Earth Overshoot Day marks the date by which the Earth’s population has prematurely used up all the raw materials that can be reproduced in the space of one year. In 2021, this point was reached on 29 July—a new, tragic record. In addition to the long-term need to stop consuming fossil raw materials, it is therefore also important that we uncover new, regenerative resources that can be used to cover our growing demand in all walks of life.
So what does this mean for the adhesives indus try? The majority of the adhesives available on today’s market are (still) based on fossil resources such as petroleum. However, Jowat has been working tirelessly on finding alternatives for many years, and with its Jowatherm® GROW and Jowatherm-Reaktant® GROW products has already launched two series of adhesives that are made partially from organic-based raw materials—in a percentage that still keeps on growing. The most important base materials for these products include substances such as crude tall oil, a by-product from the paper industry. But with demand on the rise, even a product like this isn’t always available. As such, we need to be flexible and work on additional potential sources, rather than sticking rigidly to any one path. But as Christoph Funke of Jowat’s Research and Development department is keen to stress, this is easier said ,than done. “It’s true that Jowat has already concluded research projects that looked into using plant proteins as the basis for new products,” he says. However, if the company focuses too much on extracting these proteins from peas or soya, it runs the risk of getting into a competition with the food industry, where such ingredients are increasingly being used to make vegetarian and vegan meat substitutes—products that have also seen a huge increase in demand in recent years. So what routes can Jowat look into instead? One cheap alternative that can also be produced in large quantities might be polylactide—a synthetic polymer made using lactic acid generated during biomass fermentation.
Leftover agricultural substances are particularly well-suited to use in this process, and would help us avoid getting into competition with food manufacturers. Polylactide is a promising material that is already being used as a plastic. As the basis for an adhesive, however, it still displays structural weaknesses, as Dr. Carmen Plass from Jowat Research Services department explains. “Polylactides are more brittle than other plastics, and an adhesive based on this substance would not be as resistant to heat as hot melt adhesives made from other materials.” As such, bonding using a polylactide-based adhesive would be unlikely to satisfy the high standards Jowat and its users have come to expect. “However, Jowat is already dedicating a lot of resources to researching formulations and modifications that could be used to optimize the properties of a polylactide adhesive,” she stresses. Such a product could conceivably be used in the paper industry, as well as the timber and furniture industries, which are among the biggest markes for Jowat adhesives.
A New Bonding Culture?
Microbial biopolyesters such as polyhydroxybutyrate (PHB) represent another particularly promising solution. These biopolymers, which are formed using bacteria, are biologically degradable. Several known bacterial strains, such as pseudomonas and bacillus, can produce this substance—in fact, some of them are trained or cultivated specifically for this purpose, while others are created by means of genetic modification. Metabolized PHB can only be produced through cell lysis, whereby the synthesized raw material is released into the medium so it can be extracted. Dr. Hartmut Henneken, head of Research Services at Jowat, believes that the ability to develop these types of bacterial strains opens the door to a number of new possibilities. However, there is an intermediate stage required for the manufacture of PHB-based adhesives that is currently providing a stumbling block to further progress. “The PHB needs to be used to make polyester urethane (PEU), which we can then use in turn to make adhesive. But there aren’t enough companies right now who produce PEU in large quantities.” As a result, the amounts available are not enough to cover the demand of a large manufacturing enterprise such as Jowat. “However, the availability of PHB is steadily improving, so a lot of new possibilities are opening up for manufacturers of raw materials.”
This setback has not stopped Jowat from pursuing the idea of bacterial strains—in another endeavor, the adhesive expert has commissioned Phytowelt GreenTechnologies GmbH to develop bacterial strains that produce resin acid compounds by means of genetic modification. Resin acids are an important component in many adhesive formulations. However, up until now, it has taken a huge amount of physical labor in Brazil and China to extract the necessary resins, and fluctuations in quality have also been an issue. A standardized synthetizing process using special bacteria could simplify workflows and enable use to maintain a consistently high level of quality—without having to rely on a means of obtaining raw materials that is easily compromised. “We’re still very much at the start of this journey though,” says Dr. Daniela Klein of Research Services. “The synthetic resin acids we have produced so far have been sufficient for lab analyzes, but we have a long way to go before we can begin conducting practical tests.” Nevertheless, Jowat SE won’t be giving up on these efforts just yet, and the company intends to consistently continue pursuing its august and ambitious research goals.
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