Durable Water Repellent-coating (DWR)
In the world of textiles and technical textiles, the water-repellent properties of these materials are often a critical yet extremely important characteristic. Examples include outdoor clothing, industrial applications, medical textiles, transport covers and sports textiles. Each of these applications requires reliable performance in humid conditions. One of the most commonly used solutions is a Durable Water Repellent (DWR) coating.
As a market-leading expert in innovative and technical coatings, Finipur offers advanced DWR treatments that precisely meet the needs of professional textile manufacturers and processors.
What is a DWR treatment?
A Durable Water Repellent (DWR) is a functional surface treatment that causes water to bead up on the fabric instead of penetrating it. It is an invisible chemical coating that is applied to the outside of the fabric, making the fibres hydrophobic or water-repellent. This reduces the surface tension of the fibres, preventing water droplets from being absorbed into the fabric and causing them to bead up and roll off instead.
Technically speaking, a DWR coating creates a hydrophobic nanostructure around the fibres, which means that:
- Water runs off the fabric or textile more quickly,
- The textile becomes saturated less quickly,
- The material remains lighter during use,
- The drying times of the material are greatly reduced,
- And the breathability (in membrane applications) is maintained.
Important to know:
- Not waterproof: DWR makes a garment or textile water-repellent, but not necessarily waterproof. True waterproofing usually comes from a membrane (such as Gore-Tex) that is located under the DWR-treated outer fabric. Finipur can also help you with this.
- Maintenance: The DWR coating wears off over time due to dirt, oil and washing. You can often restore its effectiveness by washing the garment with a special detergent or by adding a new DWR spray or detergent.
Different DWR technologies: PFC-free as the new standard
DWR technology has undergone a major shift in recent years, driven primarily by environmental and health concerns. Stricter regulations and growing demand for sustainable alternatives were at the root of this shift.
1. PFC-based DWRs (C6 technology)
Although C8 fluorocarbons have been virtually eliminated by environmental regulations, C6 technology is still used in applications as a transitional phase where extreme oil and water repellency is required. Finipur offers options for sectors where this performance is still indispensable, but always within the applicable standards. These C6 short-chain PFCs break down faster than C8, but they are still PFCs and still have an environmental impact.
2. PFC-free DWRs
PFC-free DWR uses alternative polymers, such as silicone- or wax-based compounds, to create a water-repellent barrier. This new generation of PFC-free formulations consists of:
- Silicone-based coatings
- Paraffin and wax dispersions
- Bio-based alternatives
Advantages:
- Environmentally friendly,
- PFC-free treatments now perform almost as well as the old PFC treatments in terms of pure water repellency. Water still beads off well.
- Excellent flex and abrasion resistance,
- Compatible with various substrate types (PES, PA, cotton, etc.).
Disadvantage:
- The main ‘disadvantage’ of PFC-free DWR is that it is not sufficiently dirt or oil repellent. Oil and fats (e.g. from sunscreen or the body's own oils) can damage the DWR coating more quickly. Oleophobicity therefore remains more limited compared to fluorinated systems.
3. Functional hybrid systems
Instead of relying solely on one type of PFC-free polymer (such as silicone or wax), at Finipur we combine different components :
- A water-repellent component: A PFC-free substance that causes water droplets to bead up.
- A reinforcing/protective component: Another type of chemical that improves adhesion to the fabric and makes the DWR layer more resistant to wear, washing and dirt.
Finipur develops these hybrid DWRs by combining different chemicals to achieve:
- Improved durability,
- Higher water repellency,
- Improved hand feel or touch
- And to guarantee optimal cost efficiency
How is a DWR coating applied at Finipur?
At Finipur, we use various industrial techniques, depending on the application and the desired end performance:
1. Pad-dry-cure
This is the most common and simplest method and ideal for large volumes and consistent results. Impregnation involves immersing the entire substrate or textile in a coating bath.
- Textiles pass through an dipping bath (pad),
- Excess liquid is squeezed out in a foulard
- The textile or substrate is passed through an oven to dry out the excess water
- Thermal fixing of the textile for chemical anchoring.
2. Coating applications (knife-over-roll or foam coating)
A squeegee coating is suitable for (technical) textiles where precise layer thicknesses are required or where the coating needs to be applied to one side only. Sometimes the fabric needs to be given multiple functions, in which case this coating application is more suitable. Some substrates are too thick or bulky to pass through a dip bath, or certain textile materials (e.g. velour) cannot be immersed in a bath without affecting their quality. Finipur will therefore determine the most appropriate technique for applying the coating for each material.
3. Spray technology
For niche applications or specific surfaces where local coating is required.
How do you evaluate the quality of a DWR?
Professional users look beyond just the ‘beading effect’. Relevant test methods include:
- Spray Test (AATCC 22 / ISO 4920)
Measures the beading level after specific cycles. - Bundesmann-test
Determines water absorption and permeability under rain conditions. - Hydrostatic Head (ISO 811)
Important for combinations with membranes. - Wash resistance tests
To evaluate durability after mechanical and thermal stress.
Finipur has a fully equipped laboratory for evaluation, development and quality control.
Conclusion
A high-quality DWR treatment is essential for any application where water repellency, durability and functionality are key. With attractive alternatives such as PFC-free systems, hybrid formulas and specialised technical coatings, Finipur offers tailor-made solutions for the most demanding industrial applications.
Would you like to know more about our DWR technologies or are you looking for a solution for your technical textiles?
Contact the experts at Finipur... we are happy to help you find the right solution.
Ready to discover the right solution for your product?