One Size Does Not Fit All in the Shift to PFC-Free DWRs

The shift to non-PFC chemistries rolls on. Recent years have seen new legislation in the EU, US and China targeting the use of perfluorinated chemicals (PFCs) and a lot of activity in the industry’s voluntary schemes, notably bluesign®, the Sustainable Apparel Coalition and Zero Discharge of Hazardous Chemicals (ZDHC).

More brands are now making the shift ahead of proposed regulations to be introduced in the EU after 2023. And those who already have PFC-free apparel in stores as part of their commitment to the ZDHC Roadmap are shifting into high gear as their transition gathers pace.

What does this mean for mills? In short, greater complexity and challenge.

DWR basics

Mills produce fabrics that repel water and other liquids by applying a treatment that lowers the surface tension of the substrate. A surface treatment based on short-chain C6 PFCs will repel water, fruit juice, red wine and hot coffee in addition to liquids with a wider range of polarities — oils, acids, blood, industrial solvents and the like. This makes these durable water repellents (DWRs) suitable for the full range of consumer and professional applications, from school uniforms and fashion raincoats to essential protective clothing for medical professionals, firefighters and so on.

PFC-free DWRs are a different story.

PFC-free chemistries available today include formulations based on paraffin, silicone, fat-modified resin, acrylate/wax and urethane. While some of these may deliver water repellency comparable to the C6 PFCs under certain circumstances, no one formulation is suitable for all applications and none can offer the high level of professional protection against oil-based liquids for essential use.

Performance considerations

When deciding which PFC-free DWR to use, it is necessary to understand the performance required of the application and this will depend on the brand, consumer and end-use article.

For example, several surveys conducted over the past few years have confirmed that water repellency and durability are of utmost importance to consumers selecting outdoor apparel, while stain resistance is of limited benefit. Protective clothing for an oil and gas industry worker, on the other hand, must repel grease and oil stains to a very high degree as these flammable contaminants can overwhelm the fire retardant properties of the clothing and increase the wearer’s risk of injury in a fire.

To summarize:

  • Water repellence is the core consideration when it comes to DWRs, but do you need protection against a light rain shower or heavy snow and sleet?
  • Stain management can help prevent fruit juice from staining a child’s school uniform or provide life-critical protection against grease stains for an oilfield worker.
  • Durability requirements also vary considerably. Will the garment be home laundered or dry cleaned? Will it be subject to heavy abrasion, as an outdoor jacket may be if the wearer is carrying a heavy backpack?
  • Compatibility with other finishes is also crucial. Does your water-repellent fabric need to be soft to the touch or to offer sun protection or to allow lamination or coating?

Unintended consequences

And there’s more. Different DWR treatment options have different effects, and not all of them are welcome.

While achieving the desired repellency with PFC chemistries demands expertise, most mills will find it to be fairly straightforward. Doing the same with non-PFCs is much more complex, and the amount of non-PFC product you need to apply can be 25-35 percent higher than a PFC to achieve the same repellency.

This higher dosage can cause unintended consequences — from adhesion issues to bonding weakness, seam slippage, chalk marks, harsh handle, and poor color fastness and shade inconsistency, not to mention cost. Depending on the end-use, some of these may be safely ignored, but others must be strenuously avoided by choosing the right chemistry, optimized recipe and application process.

So, now we have to consider water repellence, stain management, durability, compatibility and unwanted side effects and to balance these against the right cost, chemistry and eco-profile to suit the application.

Right balance

It should be clear by now that there is no one-size-fits-all solution when it comes to PFC-free chemistries.

Mills are being asked to replace a single PFC chemistry that is efficient, versatile, high-performance and suitable for a wide range of end-user applications with a system of different chemistries addressing different requirements, specifications and platforms for a variety of end uses. Indeed, the marketplace is awash with companies offering PFC-free alternatives. Not all are created equal, however. Here’s what we recommend you look for in a PFC-free partner:

  1. Product stewardship: A suitable PFC-free product must have a favorable environmental, health and safety profile. Its hazards, exposure, risk and life-cycle implications need to be understood and it must show that it complies with industry standards. A brand assurance program will give you confidence from a testing and validation standpoint that your fabric will perform to the expectations of your brand customers.

  2. A broad portfolio. To find the ideal match for your end-use article, brand and consumer, you need to be able to select from a wide range of alternatives, each delivering different levels of performance and subject to different side effects. Your partner should not only have a broad solutions portfolio, but also the research and development capability to effectively look to future trends and regulatory changes.

  3. Extensive experience. The shift to PFC-free products is chemically significant and can be challenging. For example, fabric generally must undergo more extensive pre-treatment and application rates are higher, introducing operational complexity and increasing cost. A partner should be able to offer technical support and to advise on process improvement.

The key to modern DWRs is to find the balance between what you need and what you can achieve —delivering the right performance for the desired end use without unwanted consequences while complying with frequently changing regulations, voluntary schemes and brand manufacturing restricted substances list (MRSL) limits and contributing to cleaner value chains.

It is undoubtedly complex, but taking it on a case by case basis, and with the help of a trusted partner, it can be both economically and environmentally viable.

Craig White, Global Brand Sales, Huntsman Textile Effects
Kerim Oner, Global Marketing - Finishing
Maddi Koteswara Rao, Technical Resource, Huntsman Textile Effects

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