Overview of Knitted Cloth Combined with TPU Waterproof Film

In the field of modern textile materials, composite materials of knitted fabrics and thermoplastic polyurethane (TPU) waterproof films are gradually becoming the new benchmark for high-performance protective fabrics. This innovative material has created a new era of the development of functional textiles by perfectly combining soft and breathable knitted fabric substrates with polymer waterproof films. According to a 2023 research report by the International Textile Research Association (ITRA), this composite fabric has a share of 15% in the global functional fabric market and continues to grow at a rate of 8% per year.

The core advantage of this composite material is its unique double-layer structural design: the outer layer uses high-strength, wear-resistant knitted fabric to provide excellent mechanical properties and comfortable feel; the inner layer uses a TPU with excellent waterproof performance Films form reliable barrier protection. This structure not only maintains the flexibility and elasticity of traditional knitted fabrics, but also gives the fabric excellent waterproof, windproof and breathable properties. Test data from the American Association of Textile Chemists and Dyeers (AATCC) shows that the composite fabric can be waterproofed above 5000mm while maintaining good moisture permeability (more than 5000g/m²/24h), which makes it exercise outdoors. The fields of clothing, medical protective clothing and other fields have shown significant application value.

From the perspective of market application, this new fabric is playing an important role in many fields. In terms of outdoor sports equipment, it is widely used in professional sportswear such as mountaineering suits and skiing suits; in the medical field, due to its excellent antibacterial properties and biocompatibility, it has become a medical protective product such as surgical gowns and isolation gowns. Ideal; in the field of industrial protection, its chemical corrosion resistance makes it suitable for the manufacturing of protective clothing in special working environments. According to statistics from the European Textile Technology Center (ETTC), the global market size of such fabrics has exceeded US$10 billion in 2022 and is expected to reach US$15 billion by 2027.

Analysis of material characteristics of knitted fabric and TPU waterproof film

Knitted fabrics are the base layer of composite fabrics, mainly woven from polyester, nylon or cotton fibers through knitting process, with a unique three-dimensional mesh structure. This structure gives knitted fabric excellent elastic recovery ability, its tensile deformation can reach 50-70% of the original length, and it quickly returns to its original state after removing external forces. According to research data from the Textile Institute, the breaking strength of knitted fabrics is usually between 15-30N/cm and the tear strength is about 8-12N/cm. These mechanical properties ensure the durability of the fabric in complex environments sex. In addition, the unique porous structure of knitted fabrics makes it have good breathability, and the air transmittance per unit area can reach 100-200L/(m²·s).

TPU waterproof film, as the functional layer of composite fabric, exhibits completely different material characteristics. This thermoplastic elastomer material consists of hard segments andThe soft segments are formed alternately, where the hard segment provides the mechanical strength of the material, while the soft segments impart excellent flexibility to the material. According to the technical specifications of the German Chemical Industry Association (VCI), the hardness range of TPU films is usually between Shore A60-A95 and the thickness is generally 10-50μm. Its outstanding feature is its excellent waterproof performance, and the water contact angle can be up to 110° or above while maintaining good moisture permeability. Studies have shown that the moisture permeability of TPU films can reach 3000-7000g/m²/24h, which is due to the presence of a large number of hydrophilic groups in its molecular chains, which can effectively transfer water vapor molecules.

The following is a comparison of the main performance parameters of knitted fabric and TPU waterproof membrane:

The synergy between the two materials creates an ideal composite effect: the knitted fabric provides mechanical support and comfortable feel, while the TPU waterproof membrane imparts excellent protection to the fabric. It is worth noting that the flexibility of the TPU film allows it to adapt well to the elastic deformation of the knitted fabric and avoid layering or cracking during the stretching process. This material combination can maintain a better wearing experience while ensuring functionality and meet the needs of modern consumers for high-performance fabrics.

Composite process flow and key technical points

The composite process of knitted fabric and TPU waterproof film mainly includes three core steps: pretreatment, coating, and hot pressing molding. Each link contains strict technical requirements and quality control standards. First, during the pretreatment stage, the knitted fabric needs to undergo professional surface activation treatment, including plasma treatment or corona treatment, to improve surface energy and bonding properties. This process usually requires the control of the temperature between 50-70°C and the processing time is set to 30-60 seconds to ensure surface modification while avoiding damage to the fiber structure. According to the standard testing method of the American Association of Textile Chemists and Dyeers (AATCC), the surface tension of the treated knitted cloth should reach 38-42 dyne/cm.

The coating process is a key link in the entire composite process. Advanced reverse roller coating technology is used to uniformly coat the TPU solution. Precise control of coating thickness is crucial, usually set in the range of 15-25 μm to balance waterproofing and fabric breathability. The coating speed must be maintained at 10-15 meters/min, and at the same time, a constant drying temperature curve (gradually heat up to 80-100℃) is combined to ensure that the solvent is completely volatile and the TPU film formation is uniform. In order to achieve good adhesion, a special adhesive accelerator must be added before coating, and the amount of the TPU is generally controlled between 1-3% of the total TPU.

Hot pressing is an important step afterwards and directly determines the overall performance of the composite fabric. The hot pressing process parameters need to be strictly controlled: the temperature is set at 120-140℃, the pressure range is 2-4kg/cm², and the holding time is 20-30 seconds. This process requires special attention to the uniform distribution of temperature to prevent local overheating from causing TPU degradation or shrinkage and deformation of knitted fabrics. In order to ensure the composite fastness, multiple cooling and curing treatments are required to finally form a firm molecular-level bond between the TPU film and the knitted fabric. According to the testing standards of the European Textile Technology Center (ETTC), the peel strength of qualified products should reach more than 2.5N/cm.

The following is a summary table of key process parameters:

In the entire production process, it is also necessary to establish a complete quality monitoring system, including an online inspection system and an offline sampling mechanism. The TPU film formation quality is monitored by infrared spectroscopy, the interface bonding status is checked using electron microscope, and peel strength tests are carried out regularly to ensure that the performance consistency of each batch of products meets the requirements of international standards.

Analysis of functional characteristics and application scenarios

Knitted fabric and TPU waterproof membrane composite fabric show a number of outstanding functional characteristics, making it widely used in multiple professional fields. The primary feature is its outstanding waterproof performance. According to the American Society of Materials and Testing (ASTM) D3393 standard test, the fabric has a waterproof rating of more than 8000mm, and can keep its internal dry even under continuous rainfall. This characteristic makes it an ideal choice for outdoor sports equipment, especially in extreme environments such as mountain climbing and polar adventure.

Breathable performance is another highlight of this composite fabric, with its unique microporous structure allowing water vapor molecules to pass smoothly while preventing liquid water from penetration. According to the Japanese Industrial Standard (JIS L1099) test method, the moisture permeability of this fabric can reach 6000-8000g/m²/24h, which allows the sweat vapor generated by the wearer to be discharged in time during intense exercise, keeping his body dry and comfortable. This feature is particularly well-known in the field of sportswear, such as professional running suits, cycling suits, etc.

In the field of medical protection, the composite fabric exhibits excellent antiviral and bacterial penetration properties. According to the European EN14126 standard test, its barrier rate to blood, body fluids and other biological pollutants reaches 99.9%, and it also has good biocompatibility. This makes it an ideal material for medical protective clothing such as surgical gowns and isolation gowns. In addition, the fabric also has certain antistatic properties and complies with the requirements of IEC61340-5-1, which helps to reduce safety hazards caused by static accumulation.

In industrial protection scenarios, the composite fabric exhibits good chemical protection capabilities. Through ISO6529 standard test, it has strong resistance to common organic solvents, acid and alkali solutions and other chemicals, and is suitable for special working environments such as petrochemicals and laboratories. At the same time, its wear resistance is also excellent. The Taber wear test results show that it can still maintain more than 90% of the original performance after 5,000 frictions.

The following are the main application scenarios and corresponding performance requirements:

These characteristics not only meet the professional needs of different application scenarios, but also take into account comfort and durability, demonstrating the unique advantages of this composite fabric in the field of modern protective materials.

Market competitive landscape and development trend

In the global functional fabric market, knitted fabrics and TPU waterproof membrane composite fabrics show a clear competitive landscape and development trend. According to a new report from Global Market Insights, the current market is mainly dominated by international giants such as W.L. Gore & Associates, Toray Industries, and Fruit of the Loom, a subsidiary of Berkshire Hathaway. These companies have obvious advantages in technology research and development, production capacity and brand influence. However, with the improvement of the technological strength of enterprises in Asia, especially in China and South Korea, market competition is becoming increasingly fierce. According to statistics, the market share of the Asia-Pacific region has increased from 35% in 2018 to 45% in 2022, showing strong growth momentum.

From the price positioning, the high-end market is mainly occupied by European and American brands, and its products are usually priced between $15-$25/m², while the product pricing of emerging Asian manufacturers is concentrated in the range of $10-$18/m². Although the price is relatively low, the technical level of some Asian companies is close to the international advanced level, especially in terms of production efficiency and cost control. For example, Far Eastern New Century Corporation in Taiwan, China has achieved production line automation level by introducing intelligent production equipment and increased the product yield rate to 98%.

In terms of future development trends, environmental protection and sustainability will become an important development direction. According to the Circular Economy Action Plan issued by the European Commission, the recycling rate of functional fabrics needs to reach more than 70% by 2025. To this end, many companies have begun to develop biodegradable TPU materials and recycling technologies. For example, the Ecoflex series TPU materials developed by German BASF company can have a biodegradation rate of more than 85%, while maintaining excellent physical properties. In addition, the integration of intelligent functions has also become an important trend, including the addition of functions such as temperature regulation and humidity sensing, which will further expand the application scenarios of this type of fabric.

In terms of technological innovation-driven, the application of nanotechnology is increasingly attracting attention. By introducing nanosilver particles into the TPU film, the antibacterial properties of the fabric can be significantly improved while reducing material thickness. According to research results published in the journal Nature Materials, composite fabrics using nano-enhanced technology can improve antibacterial efficiency by 30% and reduce thickness by 20%. This technological breakthrough will drive functional fabrics toward lighter weight and higher performance.

The following is a technical comparison of major enterprises:

References:

1. Global Market Insights. (2023). Functional Fabrics Market Size, Share & Trends Analysis Report.
2. European Commission. (2021). Circular Economy Action Plan.
3. Nature Materials. (2022). Advanceds in Nano-enhanced Composite Fabrics.
4. Textile Research Journal. (2023). Sustainable Development in Functional Textiles Industry.

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