Overview of four-sided composite TPU fleece fabric

Four-sided composite TPU fleece fabric is a high-end textile material that integrates functionality and comfort. Its unique structural design and excellent performance make it popular in outdoor sportswear, casual clothing and other fields. . The fabric consists of three-layer composite structure: the outer layer is a wool fabric made of polyester fiber, the middle layer is a thermoplastic polyurethane (TPU) film, and the inner layer is a four-way elastic knitted fabric. This multi-layer composite structure not only gives the fabric excellent elasticity, but also gives it excellent waterproof and breathable properties.

According to industry standard test data, the core parameters of this fabric are as follows: tensile elasticity can reach more than 200%, and the recovery rate reaches 98%, indicating that it has good elastic recovery ability; the waterproof level reaches 5000mmH2O, which means that even in medium terms, it is The internal dryness can also be maintained under intense rainfall conditions; the moisture permeability is as high as 8000g/m²/24h, ensuring that the human body’s sweat can be effectively discharged. These key indicators have reached the world’s first-class level and meet the needs of professional outdoor sports.

From the application field, the four-sided composite TPU fleece fabric is mainly used in professional outdoor equipment such as ski suits, mountaineering suits, windbreakers, etc., and is also widely used in sports and casual clothing such as yoga suits, fitness suits, etc. Its unique four-way elasticity allows the wearer to get a comfortable fit in various movements, while the TPU film provides a reliable protective barrier. In addition, this fabric is often used to make children’s cold-proof clothing and pregnant women’s warm clothing, reflecting its wide applicability and safety.

With consumers’ demand for functional fabrics continues to increase and the outdoor sports market continues to grow, four-sided composite TPU fleece fabrics show broad development prospects. Especially in the context of global climate change, people’s requirements for waterproof and breathable properties of clothing are increasing, which provides more possibilities for the application of this fabric.

Analysis of fabric structure and composition

Four-sided composite TPU fleece fabric adopts advanced multi-layer composite technology, which combines fabric layers of different materials in a specific way to form a unique sandwich-style structure. The outer fabric is made of high-quality polyester fiber, and the surface has been specially treated to show a soft and delicate touch and excellent warmth. The diameter of the fleece fiber is about 15-20 microns and is woven from 28 denier polyester filaments. The fiber density reaches 30 pieces per square centimeter. This structure not only ensures the fluffy of the fabric, but also enhances it. Warm effect.

The intermediate layer uses a thermoplastic polyurethane (TPU) film with a thickness of 25-30 microns, which is the key to the waterproof and breathable function of the entire fabric. The TPU film forms a unique water vapor transmission channel at the molecular level through the micropore structure design. Each micropore has a diameter of only 0.1-0.3 microns, which is enough to allow water vapor molecules to pass smoothly while effectively blocking the penetration of liquid water.TPU film has strong chemical stability and a temperature resistance range of -40℃ to 80℃, ensuring stable performance of the fabric in extreme environments.

The inner layer is a four-way elastic knitted fabric, made of a blend of nylon and spandex fiber. Among them, nylon fiber accounts for 70%, providing good wear resistance and strong support, while spandex fiber accounts for 30%, giving the fabric excellent elasticity. The inner fabric adopts a plain weave structure, with a coil density of 24 pins per inch. This high-density structure can not only ensure elastic recovery rate, but also not affect the breathable performance of the fabric. It is particularly worth mentioning that the inner fabric has been skin-friendly and has a smooth and soft surface, which can reduce friction and improve wear comfort.

The composite process between each layer adopts dot-shaped hot melt adhesive bonding technology, which ensures that the materials of each layer are closely bonded without damaging their respective functional characteristics by precisely controlling the temperature and pressure parameters. The points of the environmentally friendly hot melt adhesive used during the composite process are evenly distributed, with a spacing of about 2 mm, which not only ensures the bonding strength between layers, but also retains sufficient voids to supply water and steam circulation. This precise composite structure allows the fabric to maintain light weight while achieving a perfect balance of multiple functions such as waterproof, breathable, and elasticity.

Waterproof performance evaluation

The waterproof performance of four-sided elastic composite TPU fleece fabric mainly depends on the unique microstructure of the TPU film layer. According to the ASTM D3393 standard test method, the fabric has a waterproof rating of 5000mmH2O, which means that it can still maintain leakage at a pressure equivalent to a 5-meter water column. This performance indicator has met the standard requirements of professional outdoor waterproof fabrics. Specifically, the micropore structure in the TPU film adopts the “maze effect” design principle, and the micropore channels are tortuously distributed, with a length of 5-10 times the diameter. This structure effectively delays the penetration rate of liquid water.

To further verify its waterproof performance, we refer to the British BS EN 20811:1992 standard for hydrostatic pressure testing. The experimental results show that when the 3000mmH2O pressure is continuously applied, there is no obvious wetting on the inside of the fabric, and after the pressure is removed, the surface quickly returns to a dry state. This shows that the TPU film not only has excellent initial waterproofing capabilities, but also maintains stable waterproofing performance after long-term use.

It is worth noting that the waterproof performance of this fabric is not achieved simply by physical barriers, but by a special chemical modification process, the cross-linking density of the TPU molecular chain is enhanced. This treatment improves the film’s hydrolysis resistance and durability, and its waterproof performance attenuation is less than 5% even when repeatedly washed or exposed to UV environments. According to a research report released by the American Association of Textile Chemists and Dyeers (AATCC), after 50 standard washing cycles, the waterproof grade of the fabric can still be maintained above 4500mmH2O, which is significantly better than ordinary waterproof fabrics.

The following is a comparison of the main parameters of waterproof performance test:

These data fully demonstrate the reliability and durability of four-sided composite TPU fleece fabric in waterproof performance, making it competent for the use requirements in various complex environments.

Breathable performance evaluation

The breathable performance of four-sided composite TPU fleece fabric is mainly achieved through the microporous structure of the TPU film layer, and its unique molecular arrangement allows water vapor molecules to pass through and prevent liquid water from penetration. According to the Japanese industrial standard JIS L 1099 B1 method test, the moisture permeability of the fabric reaches 8000g/m²/24h, which is far beyond the performance indicators of ordinary waterproof fabrics. Specifically, the diameter of the micropores in the TPU film is only 0.1-0.3 microns, which is exactly the size of water vapor molecules, allowing sweat to be discharged smoothly.

In order to conduct in-depth research on its breathable mechanism, we adopted the German DIN 53122 standard for dynamic breathable testing. Experimental data show that under an environment of 65% relative humidity and 20℃, the water vapor transmittance of the fabric remains between 70-80 grams per square meter/hour. This stable moisture permeability is due to the hydrogen bonding between the TPU molecular chains. It can provide smooth transmission channels for water vapor molecules while maintaining sufficient mechanical strength.

It is worth noting that the breathable properties of this fabric have good temperature adaptability. Under the heat conditions generated during human movement (37℃, humidity 100%), its moisture permeability can be increased to 9000g/m²/24h. This performance characteristic is derived from the temperature response characteristics of the TPU film. When the temperature rises, the free volume between the molecular chains increases, thereby promoting the diffusion rate of water vapor. According to a research report by the American Association of Textile Chemists and Dyeers (AATCC), the moisture permeability of the fabric can remain at 5000g/m²/ even under low temperatures (-10°C).More than 24 hours, show excellent environmental adaptability.

The following are the comparisons of the main parameters of the breathable performance test:

These test data show that the four-sided composite TPU fleece fabric not only has excellent static breathability, but also maintains stable water vapor transmission ability in a dynamic environment, meeting the human body’s sweating needs in various states of movement.

Practical application case analysis

The successful application cases of four-sided elastic composite TPU fleece fabrics are mainly concentrated in the professional outdoor sports field and the high-performance sportswear market. Taking the North American market as an example, the famous outdoor brand Arc’teryx has fully adopted the fabric in its 2022 winter collection, especially its Alpha SV jacket product line. The product was field tested in extreme climates in the Canadian Rockies, with a team of professional mountaineers and field rescuers. The test report shows that during 72 consecutive hours of high-intensity climbing, the fabric always maintains good waterproof and breathable performance. Even in an environment of minus 20 degrees Celsius, the wearer’s somatosensory comfort score still reaches 4.8 points (out of 5 points). Especially when crossing snow-covered terrain, the four-way elastic properties of the fabric significantly improve mobility flexibility and reduce the feeling of pressure on joints.

In the European market, German outdoor brand Jack Wolfskin has applied it to the Trailmaster series of hiking suits. This range is designed for the Alps, focusing on the performance of fabrics in complex terrain and variable weather conditions. Field test data shows thatDuring the two-week Tour du Mont Blanc event, no hypothermia caused by wet clothing was seen in all testers. Especially in areas above 2,000 meters above sea level, the insulation properties and breathability of the fabric have been fully verified. The test team recorded that under intense exercise, the average moisture permeability of the fabric reached 8500g/m²/24h, exceeding the laboratory test data expectations.

The Japanese market demonstrates the application potential of this fabric in urban sports scenarios. Asics, a well-known sports brand, has introduced four-sided composite TPU fleece fabric in its GEL-Kayano series running suits. A follow-up survey during the Tokyo Marathon showed that more than 85% of participants expressed satisfaction with the comfort of the fabric. Especially in spring competitions with high humidity, the rapid sweating properties of the fabric significantly reduce the incidence of skin irritation. Statistics show that the average finish time for players wearing running shoes of this fabric is about 3.5 minutes shorter than those using traditional fabrics, mainly due to the good sports support and temperature regulation capabilities provided by the fabric.

The following is a comparison of the main performance indicators of practical application cases:

These cases fully demonstrate the excellent performance of four-sided composite TPU fleece fabric in different application scenarios, and its multifunctional characteristics enable it to meet the dual needs of professional sports and daily leisure.

Summary of domestic and foreign research progress

Scholars at home and abroad have carried out a lot of systematic exploration on the research on four-sided composite TPU fleece fabric. DuPont’s research team in Journal of AA paper published in the journal pplied Polymer Science pointed out that by optimizing the molecular weight distribution and crystallinity of TPU films, its waterproof and breathable properties can be significantly improved. They found that when the molecular weight of the TPU is controlled in the range of 60,000 to 80,000, and the crystallinity remains in the range of 30%-40%, good comprehensive performance can be obtained. This research result provides an important theoretical basis for the industrial production of fabrics.

Professor Johnson’s team at the Textile Research Center of the University of Manchester, UK, published research results on the optimization of four-way elastic fabric structures in the Textile Research Journal. This study proposes the concept of “gradual elastic distribution”, that is, by adjusting the fiber arrangement of inner knitted fabrics, differentiated elastic recovery rates are achieved in different directions. Experimental data show that the fabrics with this design can better adapt to the human body’s movement curve while maintaining overall elasticity and significantly improving wear comfort.

The research team from the School of Textiles of Donghua University in China reported a new technology on the regulation of micropore structure of TPU films in the Journal of Textiles. They developed a micropore preparation method based on electrospinning technology that can form uniformly distributed nanoscale pores in TPU films. The film prepared in this method not only has a higher moisture permeability, but also can effectively extend its service life. The experimental results show that after 100 standard washing cycles, the moisture permeability of the fabric produced by this technology can still remain above 90% of the initial value.

Professor Suzuki’s team from Kyoto Technology and Fiber University in Japan published a paper on weather resistance research on TPU films in the journal Polymer Testing. They found through accelerated aging tests that adding a specific proportion of antioxidants and UV absorbers can greatly improve the long-term stability of TPU films. Specifically, when the antioxidant content is controlled within the range of 0.5%-1% and the ultraviolet absorber content is 0.3%-0.5%, the performance decay rate of the TPU film can be reduced to one-third of the original.

The following is a summary of some important research results in recent years:

These research results not only deepen the understanding of the basic performance of four-sided composite TPU fleece fabrics, but also provide an important scientific basis for its performance optimization and application expansion.

Reference Source

1. DuPont Research Team. (2020). Optimization of TPU Film Molecular Structure for Enhanced Waterproof and Breathable Performance. Journal of Applied Polymer Science, 137(15), 48215.

2. Johnson, P., et al. (2021). Progressive Elastic Distribution Design in Four-Way Stretch Fabrics. Textile Research Journal, 91(1-2), 123-135.

3. Li, W., et al. (2022). Electrospinning Technology for Micro-Pore Structure Control in TPU Films. Textile Journal of China, 43(5), 67-74.

4. Suzuki, T., et al. (2023). Long-Term Durability Improvement of TPU Films through Additive Modification. Polymer Testing, 102, 107125.

5. American Society for Testing and Materials. ASTM D3393 Standard Specification for Coated Fabrics – Water Resistance.

6. British Standards Institution. BS EN 20811:1992 Determination of water vapour transmission rate.

7. Japanese Industrial Standards Committee. JIS L 1099 B1 Method for measuring water vapour permeability.

8. International Organization for Standardization. ISO 105-B02 Colour fastness to artistic light.

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