Research teams at the Fraunhofer Institute for Process Engineering and Packaging IVV are collaborating with 18 partners to tap into the potential of proteins as renewable raw materials in the chemical industry, including the manufacturing of paints and varnishes.
With the idea of using the promising technofunctional properties of vegetable proteins for industrial applications, the Fraunhofer Institute, alongside other partners, created the TeFuProt project (short for technofunctional protein), which aim is to shift away from petroleum and make more use of renewable raw materials as binding agents or adhesives for the chemical industry. This would also counteract the scarcity and long-term price increase in fossil raw materials.
Rapeseed as a source of protein
The processing of agricultural raw materials, such as rapeseed, results in large quantities of protein. These proteins are a by-product of rapeseed oil recovery, a process that presses oil out of the seed. Protein-containing by-products, so-called rapeseed meal and rapeseed press-cake, are left behind. Due to their functional properties, such as the ability to form foams, gels and films, and their ability to retain water, the protein fractions of the rapeseed press-cake have a huge potential for a broad range of technical applications: they are ideal as additives for paints, varnishes, adhesives, lubricants, building materials, detergents and polymers. This would also reduce our dependence on fossil resources and drive forward climate-friendly production.
“Up until now, this residue has been used mainly as a foodstuff in livestock farming. But this usage is limited because of the bitter substances contained”, explains Andreas Fetzer, scientist at the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising. “The vegetable proteins are opening the door to the development of novel, sustainable, bio-based products with improved properties”.
Researchers at the Fraunhofer Institute for Process Engineering and Packaging IVV were tasked with investigating how to isolate the proteins from the rapeseed meal and rape-seed press-cake and to develop the processes required.
They were also in charge of the protein modification and pre-formulation in such a way that they can be delivered to the development partners for tests either in the form of dried powders or in liquid solution. The technofunctional properties such as solubility, foaming and emulsifying behaviour, as well as film forming properties were also analysed. Besides the Fraunhofer Institute for Process Engineering and Packaging IVV, ANiMOX GmbH and Naturstoff-Technik GmbH (2014-2017) were also entrusted with manufacturing and refining the protein.
Applications in the paint and coatings industry
The film-forming properties in particular produced convincing test results.
“Upon drying proteins dissolved in water, to which a bio-based plasticizer was added, in a petri dish, the water evaporates and the proteins cross-link to form a stable film. Thus, proteins are principally suitable as alternative binding agents in paints and varnishes, wood stains or parquet coatings which usually contain petroleum-based raw materials. Acrylates, for example, can be replaced by protein preparations”, explains Fetzer.
In addition, the proteins show the ability to efficiently bind colorants or act as barriers. This showed an added benefit of the protein-based coating especially in the wood sector: the colorants were effectively prevented from “bleeding” out of the wood.
Fetzer and his colleagues successfully recovered four types of protein through four distinctly different processes.
“We de-oil, grind and dissolve the rapeseed press-cake in water. The mixture is then centrifuged to separate the solids from the liquids. After that, we refine the aqueous extract with the dissolved proteins”, says the scientist. The protein isolates recovered often have a protein content of over 90%.
The prototypes already available and what comes next
The long-term project work of the 18 partners has already produced a series of promising products, some of which are available as prototypes. These include biodegradable films as a packaging material for detergent pouches or as plant coverings, fiberboard from production residues, and binding agents modified with rapeseed protein. Flame-retardant insulating foams for the construction industry or molded foams for packaging, fiber protection and dye transfer inhibitors in eco-friendly laundry detergents, thickening components for lubricants or binders for lubricating lacquers and additives in universal cleaning agents for wood surfaces complete the list of innovative solutions.
“In many cases, we have successfully integrated the proteins into the products and generated properties with added value”, says the researcher.
The next steps aim to optimize the preparations and get them ready for the market, in order to replace petrochemical based products with bio-based ones on a large scale.