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Rudolf Group’s Durable Water-Repellent Concepts Draw from Nature

Anyone who’s ever watched a nature show on TV knows there’s no better biologist, chemist, engineer or environmentalist than Mother Nature. So a fashion-related chemical company working on eco-friendly and durable water resistance would be wise to learn from the best teacher. How do plants and animals protect themselves from the elements? How can durable materials decompose harmoniously with the planet? How can biomass replace harmful petrochemicals?

Germany-based Rudolf Group, which has been making chemicals for the global fashion industry for the past 100 years, enrolled its 85 scientists in nature’s classroom to seek such answers. The result has been fluorine-free Durable Water Repellent (DRW) technologies for both fashion and high-performance textiles.

Timing is everything. “We actually launched the RUCO-DRY product line of fluorine-free DWR technologies back in 2003, but the industry wasn’t ready for it. Now, we return to it with better-enhanced applications that focus even more on performance,” said Alberto De Conti, Rudolf Group’s head of fashion division, who is based in Italy. “Some petrochemicals might’ve given chemistry a bad name, but we’ve always been showing that chemistry can be responsible.”

Here, De Conti explains the product lines’ inspirations and applications.

SJ: Can you offer specific water-repellent methods in nature that drove your R&D into biomimicry?

AD: We had two different starting points. One was birds, namely ducks, which have to waterproof their feathers so they don’t sink. We looked at both chemical and physical components—oil and feather barb structure. Another reference was lotus leaves, which sit on water but don’t get wet or dirty. Both super hydrophobic elements in nature were very important to us and the core of our dendrimer molecular technology.

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SJ: How do Rudolf’s new Ruco Dry Bio CGR and Ruco Dry Bio NPE treatments differ in characteristics and what they’re used for? 

AD: Marketed under Rudolf Group’s Bio-Logic trademark, both provide repellency from a non-petroleum source but are quite different. RUCO®-DRY BIO CGR is the first Durable Water Repellent (DWR) agent based on plant-derived wastes, created during cereal grain processing for the food industry. We refine this material, which would otherwise be thrown out, to create a powerful water and stain repellent textile finish. While 90 percent is recycled biomass, RUCO®-DRY BIO CGR still meets the performance and durability of conventional water repellent textile finishes. RUCO®-DRY BIO NPE is a mix of oils and waxes entirely based on plant extracts, providing water- and stain-repellent effects with breathability and a natural hand feel. These are all subject to a strict conservation and sustainability framework, mainly applicable for performance outdoor and sports apparel programs. Though the results differ in cellulosic, synthetic and blends, both yield equivalent performance and offer sustainability options according to brands’ respective philosophies.

Rudolf Group
Rudolf Bionic finish Courtesy

SJ: What are the challenges to working in this natural realm vs. chemical production? 

AD: The main challenge is that Mother Nature never meant its water resistance to be applied to other substrates, have a shelf life or be machine washable. That was never Nature’s problem, but it is our problem, our need and our expectation. If you force yourself to use natural components, you face a number of problems already solved with traditional chemistry and you must return to square one to redevelop solutions. It is unlikely for pure natural components to have the exact same performance that customers are used to, because they’re just more fragile. But the ecological benefits are worth it.

SJ: What about applications that require more demanding durability?

AD: Rudolf’s new BIONIC-FINISH®ECO portfolio meets more specific expectations for tougher outdoor and sport durability, plus resistance to dry-cleaning. Utilizing patented dendrimer technology, these molecules co-crystallize and self-organize into hyper-branched polymers, which attach to the textile and embed fluorine-free, durable water-repellent performance. The key is it delivers highly efficient and durable performance but with low application amounts. Thus, softness isn’t compromised.

SJ: Are you also focusing on denim applications with these new water-resistant treatments?

AD: While our water-repellency focuses more toward outdoor and sports applications, we do have some denim programs with retailers hitting shelves this summer. These combine repellency with freshness. The driving idea is if your jeans repel most liquid spills and don’t develop odor, you don’t need to wash them so often. Color and durability will also last longer. When talking about denim water waste, everyone points their finger at industrial finishing, but most water used during denim’s lifecycle is during domestic washes. We’re a B2B company but working more on B2B2C, helping simplify the science and push the message out. If we can help brands and retailers educate their customers on behavior, that’s where a real difference can be made.

To learn more about Rudolf’s natural water-resistant technologies, click here.