Evaluation of the waterproof performance of Yuheng Tianfangs Suzhou knitted Velvet fabric

Scientific Evaluation of the Waterproof Performance of Fabrics: Taking Knitted Flannel as an Example

Among the functional attributes of textiles, water resistance has always been one of the important indicators for measuring product quality. This article will take the knitted flannel produced in Suzhou area as the research object. Through systematic experimental design and scientific data analysis, a comprehensive evaluation of its waterproof performance will be conducted, providing a reference basis for the research and development and application of related products.

I. Basic Principles of Waterproof Performance

The waterproof performance of fabrics essentially refers to the material's ability to resist the penetration of liquid water. This characteristic mainly depends on two key factors: surface tension and microstructure. When the fabric surface undergoes special treatment, its surface energy decreases, and water droplets roll in a bead-like manner due to the effect of surface tension instead of penetrating. Meanwhile, the tight fiber arrangement and special organizational structure of the fabric can also physically block the passage of water molecules.

Knitted flannel, due to its unique coil structure, usually exhibits strong water absorption when untreated. However, through post-treatment processes, such as coating treatment or the application of chemical additives, its waterproof properties can be significantly improved. To evaluate the water resistance of this type of fabric, it is necessary to consider both static and dynamic dimensions.

Ii. Experimental Design and Methods

This evaluation employs three internationally recognized testing methods to ensure the scientific nature and comparability of the results. The hydrostatic pressure test is conducted in accordance with the AATCC 127 standard. Professional equipment is used to gradually increase the water pressure until a third water droplet penetrates the fabric surface. The water pressure value at this time (unit: cmH2O) is recorded. The rain test simulates the actual usage scenario. In accordance with the ISO 22958 standard, the sample is sprayed at a specified flow rate at a specific inclination Angle, and the water penetration is calculated by the weighing method. The contact Angle measurement is carried out using an optical profilometer to analyze the morphological characteristics of water droplets on the fabric surface. An Angle greater than 90° indicates water resistance.

All samples were from the same batch of knitted flannel products and were balanced for 24 hours in a standard environment (temperature 20±2℃, relative humidity 65±2%) before testing. To eliminate random errors, each test item is repeated five times and the average value is taken.

Iii. Experimental Results and Analysis

The hydrostatic pressure test data shows that the average hydrostatic pressure resistance of the sample reaches 4200Pa, which is equivalent to approximately 42.8cmH2O. This value indicates that the knitted fleece fabric can effectively resist the infiltration of medium and light rainfall, meeting the basic requirements of outdoor casual wear. It is worth noting that when observed under an electron microscope magnified 200 times, the treated fiber surface forms a uniform nanoscale raised structure. This lotus leaf-like effect significantly enhances the waterproof performance.

In the rain test, the average water permeability after 30 minutes of continuous spraying was 3.2%, which was better than the 25.7% of similar untreated knitted fabrics. It is particularly worth noting that after multiple washes (standard 5 times), the waterproof performance retention rate still reached 82%, indicating that the treatment process has good durability. The contact Angle measurement results show that the initial contact Angle is 138°, which falls within the category of superhydrophobic materials. This is in line with the microscopic structure observation results.

Iv. Discussion on Influencing Factors

The influence of ambient temperature on waterproof performance shows nonlinear characteristics. When the temperature rises from 10℃ to 30℃, the contact Angle decreases by approximately 8°. This might be due to the intensified molecular movement of the surface treatment agent caused by the temperature increase. In addition, the stretching deformation of the fabric can also affect the waterproofing effect. When stretched by 10% in the warp direction, the hydrostatic pressure value drops by 15%, which reminds us that we need to consider the waterproofing treatment at the seams when designing clothing.

Compared with similar products in other regions, the waterproof durability of this sample stands out. This might be attributed to a special crosslinking agent application process, which enables the waterproofing agent to form a stable chemical bond with the fibers rather than a simple physical adhesion.

V. Application Suggestions and Prospects

Based on the test results, this type of knitted velvet fabric is suitable for making lightweight waterproof jackets, outdoor sportswear and other products. In terms of usage and maintenance, it is recommended to use neutral detergent and avoid high-temperature ironing to extend the waterproof life. Future research can focus on the development of environmentally friendly waterproofing agents and how to balance the contradictory indicators of waterproofing and breathability.

With the growth of consumers' demand for functional textiles, waterproof performance will become an important competitive edge for knitted products. Through continuous technological innovation and rigorous performance evaluation, the textile industry can provide the market with more superior solutions. This evaluation not only verified the performance indicators of specific products, but also provided practical references for the industry to establish a scientific evaluation system.