Introduction
As people’s living standards continue to improve, more and more textiles are endowed with functional properties, and water repellency is one of the important properties. Waterproof fabrics are highly valued because they can effectively repel water, so they are widely used in workwear and casual jackets. However, with the increasing restrictions on the use of fluorinated organic polymers, the development of environmentally friendly fluorine-free waterproof finishes has become a new research focus and has gained a lot of market attention.
Our company produces fluorine-free waterproof fabrics that not only meet environmental standards but also have excellent water resistance, which are suitable for workwear, jackets, and other functional apparel. However, in the process of use and testing, we found that the water resistance of fluorine-free waterproof fabrics would decrease after washing, mainly because of the lower stability of fluorine-free waterproof finishes.
In the production process, many factors will affect the effect of fluorine-free waterproof finishes, but the drying method and washing times after laundering are particularly important. This article will analyze experimental data to explore how these factors affect the effect of fluorine-free waterproof fabrics and provide optimization suggestions.
Experimental Section
To evaluate the effect of different drying methods and washing frequencies on the water resistance of fluorine-free waterproof fabrics, we randomly selected eight fabric samples treated with a fluorine-free waterproof finish. These samples had different colors, patterns, and structures. We used the same washing method and procedure for all samples, but we used different drying methods after washing. We then tested the water resistance of the samples using a spray test to see how washing and drying affected the water resistance.
Experimental Methods
Experiment 1: Before washing, the samples were tested for water resistance.
Experiment 2: The samples were washed three times using the 4N program (according to the GB/T 8629—2017 standard) and air-dried.
Experiment 3: The samples were washed three times using the 4N program and dried at 50°C in a tumble dryer.
Experiment 4: The samples were washed three times using the 4N program and dried at 70°C in a tumble dryer.
Experiment 5: The samples were washed three times using the 4N program and dried at 80°C in a tumble dryer.
Experiment 6: The samples were washed 3, 10, 20, and 30 times using the 4N program and dried at 70°C in a tumble dryer.
Experimental Results
1. The effect of different drying methods on the water resistance of the fabric after washing
The test results for the eight fabric samples are as follows:
| Sample | Before wash | Air-dried | 50℃ tumble dry | 70℃ tumble dry | 80℃ tumble dry |
| 1 | 5 | 2 | 3 | 4-5 | 4-5 |
| 2 | 4 | 1 | 2 | 3-4 | 4-5 |
| 3 | 5 | 2-3 | 4 | 5 | 4-5 |
| 4 | 5 | 3 | 3-4 | 4-5 | 5 |
| 5 | 4-5 | 1-2 | 3 | 4 | 4-5 |
| 6 | 4-5 | 2-3 | 4 | 4-5 | 5 |
| 7 | 5 | 2 | 3-4 | 5 | 5 |
| 8 | 5 | 3 | 4 | 4 | 4 |
The data shows that all samples had a high water resistance rating before washing. After three washes, the water resistance ratings of the samples varied significantly depending on the drying method used. The air-dried samples showed the greatest decline in water resistance, dropping by 50% or more. Conversely, the samples dried in a tumble dryer exhibited an increase in water resistance as the drying temperature rose. The improvement in water resistance leveled off at 70°C, indicating that a household drying temperature of 60°C or higher is sufficient for maintaining the water resistance of waterproof fabrics.
Analysis of Experimental Results: The reason for the observed differences is that the molecules of the waterproof finish are arranged neatly and uniformly on the surface of the fibers during processing, which results in good water resistance. However, washing disrupts this orderly arrangement, causing the molecules to bend or collapse on the fiber surface. Without the neat arrangement of the waterproof finish, hydrophilic polar groups are exposed, leading to a reduction in water resistance.
Using high-temperature drying methods after washing helps the molecules of the waterproof finish realign on the fiber surface, potentially restoring the water resistance to its pre-wash state. Therefore, the post-wash drying method is a crucial factor in maintaining the water resistance of waterproof fabrics.
2. Impact of Washing Frequency on Fabric Water Resistance
The eight samples treated with a fluorine-free waterproof finish were tested according to Experiment 6 to evaluate the effect of washing frequency. The specific test results are as follows:
| Sample | Before wash | 3 washes | 10 washes | 20 washes | 30 washes |
| 1 | 5 | 4 | 4 | 3 | 1-2 |
| 2 | 4 | 3-4 | 3-4 | 2 | 1-2 |
| 3 | 5 | 3-4 | 3 | 2-3 | 2 |
| 4 | 5 | 4 | 3 | 3 | 1-2 |
| 5 | 4-5 | 3-4 | 3-4 | 2-3 | 1 |
| 46 | 4-5 | 4 | 3 | 3 | 1-2 |
| 7 | 5 | 4 | 3-4 | 3 | 1 |
| 8 | 5 | 4 | 4 | 3 | 2-3 |
The data shows that as the number of washes increases, the water resistance of the samples decreases. After 20 washes, 40% of the samples showed a significant decline in water resistance, while 60% of the samples lost almost all water resistance. After 30 washes, all eight samples completely lost their water resistance. This decline is primarily due to the gradual disintegration and removal of the waterproof finish molecules from the fabric surface, resulting in poor wash resistance and ultimately affecting water resistance.
Conclusion
In daily use or fabric testing, the washing frequency and post-wash drying method significantly impact the water resistance of fluorine-free waterproof fabrics. Air drying causes the greatest decline in water resistance, with a reduction of 50% or more. In contrast, high-temperature drying (above 60°C) helps maintain water resistance, with the improvement leveling off at 70°C. However, the irreversible impact of repeated washing means that after 30 washes, the fabric will lose most of its water resistance.
To maintain the best performance of waterproof fabrics, our company recommends the following:
- Tumble dry at 70°C after washing: This method effectively restores the fabric’s water resistance.
- Reduce washing frequency: Minimize unnecessary washing to prolong the life of the waterproof finish.
- Use neutral detergent: Regular detergents may damage the waterproof coating, so using a neutral detergent helps reduce harm.
- Spot clean when possible: For localized stains, use a damp cloth to clean the area rather than washing the entire garment, thereby avoiding over-washing.
Our company’s fluorine-free waterproof fabrics are environmentally friendly and have good water resistance. They are suitable for work clothes, jackets, and other applications. We will continue to innovate and provide customers with better waterproof fabric solutions.