Is there such thing as a natural coating?
What do you know about chemicals? Are they essential in our everyday life? Is there something like ‘good’ or ‘bad’ chemicals? In our series ‘Stahl Explains’, our chemists and researchers will give clear answers to most frequently asked questions. This week, Frank Brouwer explains if there is such thing as natural coatings:
Yes, there is. But before we will go into-details, let’s first define the term ‘natural’. As public interest in sustainability continues to climb you also see terms like natural and organic popping-up more often. Especially in cosmetics where consumer perception is that natural ingredients are safer. To provide guidelines on definitions and criteria for natural and organic cosmetic ingredients ISO 16128 was developed, and although coatings are not part of this ISO 16128 norm we believe it can also provide some guidance here. ISO 16128 states that natural ingredients are obtained from plants, animals, microbiology, or are from mineral origin. They can be obtained either by physical processes (e.g. grinding, drying, distillation, etc.), natural occurring fermentation reactions (leading to molecules which occur in nature) or other chemical processes (e.g. extraction using solvents), but without intentional chemical modification. Naturally derived ingredients are ingredients which are for more than 50% (by molecular weight) of natural origin, obtained through defined chemical and/or biological processes with the intention of chemical modification. Ingredients from petrochemicals are excluded from these definitions.
So where can we find natural coatings? They are commonly put on our foods to prevent moisture loss and bruising during shipping. Examples are polysaccharides (cellulose, starch, dextrin, chitosan and other gums, etc), proteins (gelatin, gluten, casein, etc) and waxes (shellac, carnauba- or bees wax, etc). Interestingly these coatings could also be found on our leather products in the good old days; before they were replaced by natural derived coatings like modified cellulose and later by synthetics like polyurethanes and polyacrylates. Mainly because of their ease of application and better performance. With an increased interest on end of life of materials and the use of natural substrates, the focus on these natural coatings is increasing; but is going back the right choice? It is now the question how we can combine durability, performance and end-of-life in one type of coating; it is about matching performance with end-of-life degradability. Within EU-funded projects like BioNIPU and CHAMPION Stahl is partnering with private companies and research institutes to resign our synthetic materials to bring performance, while being plant based and have a controllable end-of-life. These project just have started, for the ones who cannot wait, we already developed some renewable resins, some containing more than 50% plant based materials; you could say a natural derived coating.
Want to know more about coatings? Read our Stahl Explains:
'Why are there so many types of coatings?'
'What would happen if there were no coatings?'
'What is a coating or paints? Are they the same?'
'How do we design our coatings?'
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