Biodegradable fabric coatings are redefining the textile industry, offering eco-friendly alternatives to traditional coatings like PFAS, vinyl, and polyurethane. Here's a quick comparison:
- Biodegradable Coatings: Made from renewable resources like soy protein and chitosan, they reduce environmental pollution, decompose naturally, and support recycling efforts. However, they face challenges like higher costs, limited durability, and availability.
- Traditional Coatings: Known for their durability and high performance, these coatings (e.g., PFAS-based) are widely used but pose significant health and environmental risks due to their persistence and toxicity.
Quick Comparison
| Feature | Biodegradable Coatings | Traditional Coatings |
|---|---|---|
| Materials | Soy protein, chitosan, plant-based polymers | PFAS, vinyl, polyurethane, acrylic |
| Environmental Impact | Decomposes naturally, lower emissions | Persistent, contributes to pollution |
| Performance | Moderate durability, requires reapplication | High durability, long-lasting |
| Applications | Outdoor gear, medical textiles, apparel | Industrial uniforms, aerospace materials |
| Cost | Higher upfront cost | More affordable upfront |
Biodegradable coatings are a step forward in reducing the textile industry's environmental footprint, but they still need advancements in durability and cost-efficiency to match traditional options. Dive into the full article to explore performance tests, market trends, and industry innovations.
Standard Fabric Coatings: Main Features
Common Coating Types
Fabric coatings often rely on materials like vinyl, silicone, polyurethane, and acrylic to improve textile durability and functionality [1].
| Coating Type | Benefits | Drawbacks |
|---|---|---|
| Vinyl | Waterproof and budget-friendly | Poor breathability, may crack in the cold |
| Silicone | Heat and chemical resistant | Expensive and less flexible |
| Polyurethane | Water-resistant and breathable | Limited UV resistance |
| Acrylic | UV resistant and retains color well | Weak water resistance |
Coatings made with PFAS play a major role in the textile industry, accounting for roughly 35% of global PFAS use. Within the EU, the textile sector alone uses between 41,000 and 143,000 tonnes of PFAS annually [2]. These formulations directly impact the performance of coated fabrics, as explained below.
Effectiveness Metrics
PFAS-based coatings are known for their strong oil and water repellency when conditions are optimal [4]. The water-repelling ability is evaluated using contact angles - any angle over 90° indicates a hydrophobic surface. Fabrics treated with dip-finishing methods tend to offer more consistent protection compared to foam-applied finishes [4].
While these coatings perform well in controlled settings, they bring significant health and environmental concerns.
Safety and Risk Factors
Many traditional coatings, especially those containing PFAS, raise serious health and environmental issues. Professor Graham Peaslee from Notre Dame highlights this danger:
"Once these chemicals are used, they get into the groundwater, they get into our biological systems, and they cause significant health problems" [5].
The main concerns include their persistence in the environment, ability to accumulate in living organisms, and potential health effects. For instance, studies reveal that 97% of Americans have detectable levels of PFAS in their systems [4].
In response to these risks, companies like W.L. Gore have taken action. In 2023, the company committed to eliminating all harmful per- and polyfluorinated chemicals from its consumer laminate products [6].
Performance Without PFAS Chemicals
Biodegradable Coatings: New Solutions
Unlike PFAS-based coatings, biodegradable alternatives aim to reduce environmental harm while tackling new performance challenges.
Materials and Methods
Biodegradable coatings rely on bio-based polymers from renewable resources. These include materials like cutin, chitosan-chitin complexes, and protein-based solutions, which balance functionality and eco-friendliness [8].
Here’s a breakdown of key materials and their uses:
| Material Type | Key Properties | Applications |
|---|---|---|
| Soy Protein | Excellent oxygen barrier - rivals polyethylene (PE) | Packaging, protective garments |
| Chitosan-Chitin | Antimicrobial and water-repellent | Medical textiles, athletic wear |
| Plant-based Polymers | Biodegradable water resistance | Outdoor gear, daily clothing |
| Cross-linked Siloxanes | High water repellency and durability | Performance wear, workwear |
For instance, Empa has developed a PFAS-free siloxane coating applied via plasma technology. At just 30 nanometers thick, it provides excellent water repellency and breathability [12]. These advancements not only improve performance but also offer practical benefits.
Main Advantages
Biodegradable coatings bring several key benefits:
- Reduced Environmental Impact: These coatings decompose naturally, unlike PFAS-based options that persist in the environment.
- Improved Safety: Natural materials lower the risk of exposure to harmful chemicals, especially in products that come into direct contact with skin.
- Support for Recycling: These materials align with recycling and upcycling efforts [9].
The textile industry produces 92 million tons of waste annually [9], highlighting the need for solutions like these.
"By mimicking nature's chemistry, we have developed our effective and eco-labelled textile and shoe waterproofing... Our products are biobased, biodegradable and PFAS-free - so nothing is left in nature."
– OrganoTex [11]
Current Limitations
While promising, biodegradable coatings face a few hurdles that need addressing to compete with traditional alternatives.
MIT researchers have worked on improving durability. Lead researcher Dan Soto explains:
"The biggest challenge was finding the sweet spot where performance, durability, and iCVD compatibility could work together and deliver the best performance." [7]
Some challenges include:
| Challenge | Impact | Industry Response |
|---|---|---|
| Limited Availability | Restricted market access | Scaling up production |
| Higher Production Costs | Premium pricing | Research into cost-efficient methods |
| Durability Concerns | Shorter lifespan compared to PFAS coatings | Enhanced formulations under development |
Companies like OrganoTex are making strides. Their Industrial DWR coating maintains high performance for over 20 laundry cycles on synthetic fabrics while adhering to biodegradability standards [10].
Performance Tests and Results
Performance tests reveal important differences between biodegradable and traditional fabric coatings.
Test Categories
The Hohenstein Institute uses a detailed framework to assess coatings based on four key parameters:
| Test Parameter | Measurement Method | Industry Standard |
|---|---|---|
| Water Resistance | Static water contact angle (WCA) | Over 150° for superhydrophobic surfaces |
| Breathability | Ret value (resistance to evaporative heat loss) | Below 40 m²Pa/W for good breathability |
| Durability | Wash cycles and abrasion resistance | Minimum of 10 wash cycles |
| Stain Protection | Multi-liquid contact angle test | Over 145° for effective repellency |
While cup methods are a quick and budget-friendly option for production checks, true breathability is better assessed using the skin model.
"For production control, the cup methods can offer a relatively quick and, above all, cheap solution. However, how the breathability of a textile is perceived when it is worn can only be measured using the skin model" [13].
These parameters provide a foundation for comparing liquid repellency and laundering durability.
Water and Liquid Repellency
Traditional fluorochemical coatings typically achieve contact angles between 127° and 135°. In contrast, biodegradable CAHPS coatings reach 145°–150° under controlled conditions. Even when exposed to liquids like salt water, tea, and cola, treated fabrics maintained contact angles of 147°–150°, showing strong repellency.
Durability Under Laundering
Durability is essential to retaining functional properties over time. Washing tests at 104°F revealed a decline in waterproofness for biodegradable coatings: from 992 mbar to 246 mbar with a specialized detergent, and further to 122 mbar with a universal detergent after 10 cycles [14]. While traditional coatings outperform in durability, biodegradable options may need more frequent reapplication to stay effective.
sbb-itb-3ba7a4c
Product Uses by Industry
Clothing and Fashion
PFAS-free, eco-friendly coatings are transforming the textile industry. One standout is BIONIC-FINISH® ECO, which incorporates up to 90% renewable bio-based materials[15]. These advancements are steering the industry toward high-performing solutions that avoid traditional fluoropolymer coatings, which are under growing regulatory scrutiny. Manufacturers are increasingly turning to short-chain alternatives to comply with these changes.
| Coating Type | Bio‑based Content | Application |
|---|---|---|
| RUCO‑DRY® BIO CGR | 87% | Premium outerwear |
| RUCO‑DRY® ECO ADV | 74% | Everyday wear |
| RUCO‑DRY® ECO NCB | 43% | Athletic apparel |
| RUCO‑DRY® ECO PLUS | 42% | Casual clothing |
Sports and Outdoor Equipment
These advanced coatings are also making waves in outdoor gear. Industries rely on them for durability and performance under challenging conditions. Dr. Torsten Pohl, Head of Global Textile Coatings at Covestro, highlights their innovative approach:
"In response to tough environmental challenges in the textile coating industry, Covestro has changed the game with the INSQIN® polyurethane technology. These waterborne and partly bio‑based or bio‑degradable polyurethanes enable our customers to produce textile products with high‑performance, durability, soft touch, amazing appearance, and with enhanced sustainability."[16]
INSQIN® waterborne PU coatings offer a significant advantage, with over 50% degradation achieved within 28 days, according to the OECD Test Standard 301[16]. They also reduce VOC emissions compared to traditional solvent-based coatings, making them a more environmentally friendly choice.
Home Products
Sustainable coatings are now gaining traction in home textiles as well. With synthetic fibers making up 70% of household textiles[18], the demand for biodegradable options continues to grow. OrganoClick addresses this need with their innovative solution:
"What we replace is often hidden plastics and harmful chemicals that many may not even realize are present inside the materials. We call it Made Green Inside by OrganoClick®."[17]
OrganoClick's OC‑BioBinder® technology enables home-compostable options for furniture and decorative textiles[17]. The focus is on factors like storage stability, cost efficiency, batch consistency, and the impact of raw material sourcing.
As global green initiatives gain momentum, the textile coating market is expected to expand by 4.93%, potentially adding $9.59 billion in revenue by 2031.
Impact on Environment
Production Impact
Traditional coating methods come with serious environmental concerns. The use of fluorochemicals produces harmful byproducts like PFOA and PFOS, which pose risks to both ecosystems and human health [3].
Different coating types have varying environmental footprints:
| Impact Factor | Traditional Coatings | Biodegradable Coatings |
|---|---|---|
| GHG Emissions | Baseline | 75% reduction [19] |
| Energy Usage | Standard process | 35% less non-renewable energy [19] |
| Solvent Use | High volume | Up to 80% reduction [20] |
| CO2 Output | Higher emissions | 60,000 metric tons less annually* [20] |
*Data based on a 250,000-metric-ton production facility using gas-phase technology.
Rebecca Lucore, head of sustainability at Covestro LLC, highlights the importance of scalable solutions:
"It's important to aim to reduce impacts on multiple levels (energy use, resources and emissions, cost effectiveness, and increased productivity), but it is equally important that any reduction technologies have the potential for scale in other regions and possible expansion to other applications so that their benefits are appreciably widespread" [20].
The challenges tied to production also lead to significant waste management concerns.
Waste Management
Each year, between 0.8 and 2.5 million metric tons of primary microplastics enter the oceans. Textile coating abrasion during washing is responsible for 35% of this pollution [21]. While wastewater plants filter out over 98% of microplastics, the remaining particles still contaminate water systems.
Natural fiber-based coatings treated with amino-functional silicone softeners show promise, improving biodegradability by 5.5% compared to conventional treatments [21]. However, using DMDHEU resin can reduce biodegradation rates by 6.5% [21].
These waste issues, combined with the long-term impact of coatings, emphasize the need for sustainable alternatives.
Long-term Effects
Covestro's adoption of gas-phase technology offers substantial environmental benefits, including:
- 60% lower energy consumption
- 80% reduction in solvent use
- Significant decrease in CO2 emissions [20]
The growing demand for biodegradable solutions is reflected in the chitosan market, which is expected to expand from $1.65 billion in 2019 to $4.4 billion by 2027 [8]. This shift is driven by rising environmental awareness and stricter chemical regulations.
Bill Schillinger, PPG's global director of manufacturing technology, states:
"The 12 Principles of Green Chemistry provide PPG employees with a developmental roadmap for sustainable efforts that helps us to improve efficiency and drive down our impact on the environment." [20]
While traditional coatings are known for their durability, their environmental persistence underscores the industry's growing shift toward biodegradable options, aligning with broader sustainability efforts.
Industry Changes and Research
Market Direction
Recent market trends, influenced by performance reviews and environmental studies, are steering the industry toward PFAS-free alternatives. This shift is particularly noticeable in sectors like performance wear and outdoor apparel, where environmental concerns and stricter regulations are driving change:
| Segment | Current Status | Next Steps |
|---|---|---|
| Performance Wear | Moving away from PFAS | Accelerating the shift to PFAS-free options |
| Outdoor Apparel | Limited PFAS-free offerings | Expanding the range of PFAS-free choices |
NordShield® is a standout example of this movement. The company has created textile protection solutions that replace heavy metals with eco-friendly alternatives while maintaining top-tier performance. Their CEO, Paul Wasastjerna, highlights their mission:
"Our commitment to nature and sustainability is in our DNA. It reflects our deep Nordic roots. We are on a mission to create the best tomorrow for our planet and the life on it - NordShield® is the answer." [25]
Policy Changes
Legislation in New York State is set to prohibit the intentional addition of PFAS to general apparel starting January 1, 2025, and to outdoor apparel designed for severe wet conditions beginning January 1, 2028 [24]. The law defines intentionally added chemicals as those included for a specific technical purpose in a product or its components, covering PFAS and their breakdown products [24].
These legal changes are spurring rapid advancements in fabric coating technologies.
New Technologies
Innovations in fabric coatings are reshaping the industry. The Swiss Federal Laboratories for Materials Science and Technology (Empa) has developed a plasma coating process using siloxanes to create an ultra-thin protective layer [23]. Dr. Dirk Hegemann from Empa explains:
"We have even succeeded in permanently impregnating more demanding elastic fibers with the new process, which was previously not possible." [23]
Biodegradable polyurethane (PU) coatings are also showing progress, with tests revealing 50% degradation within two months, 60% in soil after 180 days, and 80% relative biodegradation compared to a cellulose reference [22]. Swiss textile companies like Lothos KLG, beag Bäumlin & Ernst AG, and AG Cilander are already incorporating these eco-friendly solutions, further signaling the industry's shift toward sustainable practices.
Conclusion
Main Findings
Biodegradable coatings offer a mix of benefits and challenges when compared to traditional coatings. For instance, biodegradable PU coatings degrade about 60% in soil within 180 days, whereas conventional PLA requires industrial composting to break down. On the performance side, products like PolyCore Eco-Coating increase abrasion resistance by over 500% while cutting CO2e emissions by 1.69 pounds per yard of fabric [26].
| Aspect | Biodegradable Coatings | Traditional Coatings |
|---|---|---|
| Environmental Impact | Lower microplastic pollution; ~60% soil degradation in 6 months [22] | Contributes to environmental pollution |
| Performance | Flexible but lower elongation (<300%) | More durable with higher elongation |
| Applications | Suited for rainwear, tents, and food packaging | Versatile for high-performance uses |
| Cost Impact | Higher upfront cost, long-term environmental benefits | Lower cost, higher environmental toll |
These findings provide a clear framework for selecting the right coating based on specific needs.
Buying Guide
When choosing fabric coatings, here are some key considerations based on the findings:
- For performance wear, aim for a balance between durability and environmental impact. Water-based PU coatings are a solid choice as they reduce VOC emissions while maintaining effectiveness [26].
- For healthcare and industrial settings, prioritize coatings that can handle frequent cleaning and meet chemical safety standards. Look for materials with transparent ingredient disclosures and certifications like bluesign® approval [26].
- For consumer products, think about the usage environment. Biodegradable PU coatings work well in moderate conditions but may not hold up under extreme hydrolysis [22].
"Using our water-based coating allows manufacturers to create products that are made to last a lifetime and have a lower environmental impact. We want Eco-Coating to be the next sustainability milestone in the textile industry."
- PolyCore Solutions [26]
