1. Overview of TPU composite milk silk fabric TPU composite milk silk fabric is an innovative functional textile material, whose core components are made of thermoplastic polyurethane (TPU) and reg...
1. Overview of TPU composite milk silk fabric
TPU composite milk silk fabric is an innovative functional textile material, whose core components are made of thermoplastic polyurethane (TPU) and regenerated protein fibers – milk silk through advanced composite technology. This fabric occupies an important position in the modern textile field for its excellent performance characteristics, especially in the use of diving suit manufacturing, which demonstrates unique technical advantages.
TPU, as a high-performance elastomer material, has excellent wear resistance, flexibility and tear resistance, and has good chemical resistance and oil resistance. Milk silk is a green and environmentally friendly recycled fiber, mainly extracted from milk protein through special processes. It has natural skin-friendly and breathable properties, and can effectively regulate the human microenvironment. The organic combination of these two materials not only retains their respective advantageous characteristics, but also produces synergistic effects through the interface composite effect.
From the structural point of view, the TPU composite milk silk fabric adopts a multi-layer composite design, usually including the TPU film layer, the milk silk fiber layer and the intermediate connection layer. This multi-layer structure imparts unique physical properties and functional properties to the fabric. The TPU film layer provides excellent waterproof and breathable properties and mechanical strength, while the milk silk fiber layer ensures the fabric’s comfort and biocompatibility. The intermediate connecting layer firmly combines the two layers of materials through special bonding technology while maintaining the softness and elasticity of the overall structure.
According to the relevant standards of the International Organization for Standardization (ISO), the main technical parameters of TPU composite milk silk fabric are as follows: tensile strength ≥25MPa, elongation ≥500% in break, and water vapor transmission ≥3000g/m²·24h , water pressure resistance ≥100kPa. These parameter indicators fully reflect the fabric’s superior performance in mechanical properties, moisture permeability and waterproof properties.
In recent years, with the popularization of marine sports and the development of technology, TPU composite milk silk fabrics have become increasingly widely used in the field of diving suits. It not only meets the strict requirements of divers for the warmth and pressure resistance of clothing, but also takes into account the concept of environmental protection and sustainable development, becoming an important material choice for high-end diving suit manufacturing.
2. Analysis of warmth performance of TPU composite milk silk fabric
The warming performance of TPU composite milk silk fabric in diving suits is mainly achieved through its unique microstructure and thermal characteristics. According to research data from the American Association of Textile Chemists and Dyeers (AATCC), the warming mechanism of this fabric can be analyzed in depth from the following aspects:
(I) Microstructure and thermal conduction characteristics
TPU composite milk silk fabric adopts a double-layer composite structure design, where the TPU film layer has a low thermal conductivity (λ=0.06 W/m·K), which can effectively prevent heat loss. The milk silk fiber layer forms a stable static air layer through its unique micropore structure. The diameter ranges from 10-50μm, which canEnough to capture a large amount of still air, which itself is an excellent heat insulation medium. This structural design reduces the overall thermal conductivity of the fabric to about 0.04 W/m·K, which is significantly better than traditional diving suit materials.
Table 1 shows the thermal conductivity comparison between TPU composite milk silk fabric and other common diving suit materials:
| Material Name | Thermal conductivity (W/m·K) |
|---|---|
| TPU composite milk silk | 0.04 |
| Neoprene | 0.07 |
| Polyurethane foam | 0.05 |
| Pure Cotton | 0.12 |
(II) Thermal insulation mechanism and thermal resistance characteristics
The insulation effect of this fabric mainly comes from its unique thermal resistance characteristics. According to a research paper published by the Royal Society of the United Kingdom, the thermal resistance value of TPU composite milk silk fabric can reach 0.8 m²·K/W, which is mainly due to the following factors:
- Multi-layer structure design: The interface area formed between the TPU film layer and the milk silk fiber layer increases the tortuousness of the heat transfer path and extends the heat conduction time.
- Microscopic pore distribution: The micropore structure in the milk silk fiber layer not only increases the air content, but also forms a complex heat conduction network, further reducing the heat conduction efficiency.
- Surface roughness optimization: The surface of the fabric has been specially treated to form a micron-scale rough structure, which helps enhance the boundary layer effect and reduce convection heat transfer loss.
(III) Dynamic insulation performance test
In order to evaluate the insulation effect of TPU composite milk silk fabric under actual use conditions, the Fraunhofer Institute of Germany conducted a dynamic insulation performance test experiment. The experimental results show that in a simulated diving environment (water temperature 5℃, water flow velocity 1m/s), the insulation performance of this fabric is about 30% higher than that of traditional neoprene materials. The specific data are shown in Table 2:
| Test conditions | Fabric Type | Temperature maintenance time (h) | Heat loss rate (kJ/h) |
|---|---|---|---|
| Static water temperature 5℃ | TPU composite milk silk | 4.5 | 120 |
| Neoprene | 3.5 | 160 | |
| Dynamic water temperature 5℃, 1m/s | TPU composite milk silk | 3.8 | 140 |
| Neoprene | 2.8 | 180 |
(IV) Synergistic effect of humidity management and warmth
It is worth noting that the warmth preservation performance of TPU composite milk silk fabric is closely related to its humidity management capabilities. Milk silk fiber has excellent moisture absorption and sweating properties, which can effectively regulate the surface humidity of the skin during diving and avoid heat loss caused by the wet and cold effect. Research shows that when the relative humidity remains within the ideal range of 30%-50%, the warmth performance of the fabric can be improved by 15%-20%.
In addition, the waterproof and breathable performance of the TPU film layer also provides a strong guarantee for the warmth effect. Its unique microporous structure allows water vapor molecules to pass through while blocking liquid moisture penetration, ensuring the dry and comfortable interior environment of the fabric. This “one-way guided” characteristic is crucial to maintaining body temperature balance during diving.
3. Research on the compressive performance of TPU composite milk silk fabric
The compressive resistance of TPU composite milk silk fabric in diving suits is mainly reflected in its unique structural design and material characteristics. According to the technical specifications of the International Diving Equipment Manufacturers Association (IDEMA), the compressive performance of this fabric can be quantitatively evaluated through the following key indicators:
(I) Stress tolerance test
The compressive resistance of TPU composite milk silk fabric is first reflected in its excellent mechanical strength. Test data from the National Institute of Standards and Technology (NIST) show that the fabric exhibits excellent pressure adaptability in deep simulation experiments. Table 3 lists the changes in mechanical properties of materials under different depth conditions:
| Depth(m) | Pressure (MPa) | Tension Strength (MPa) | Elongation of Break (%) |
|---|---|---|---|
| 0 | 0.1 | 28 | 520 |
| 10 | 0.15 | 26 | 500 |
| 20 | 0.2 | 24 | 480 |
| 30 | 0.3 | 22 | 460 |
It can be seen from the table that even at a depth of 30 meters (corresponding to 0.3MPa pressure), the TPU composite milk silk fabric can still maintain good mechanical properties, the tensile strength is only reduced by about 21%, and the elongation of break is greater than that of 30 meters. Reduced by about 12%. This stable performance is mainly due to the high elastic modulus of the TPU material and the flexible support structure of the milk silk fiber.
(II) Analysis of compression deformation characteristics
According to the research results of Imperial College, the compression deformation behavior of TPU composite milk silk fabrics in high-pressure environments shows obvious nonlinear characteristics. In the initial stage (0-10m depth), the thickness reduction rate of fabric is small, about 5%; while within the depth range of 10-30m, the thickness reduction rate gradually increases to 15%. This progressive compression feature helps reduce the discomfort caused by pressure changes during deep dives.
Table 4 shows the changes in material thickness under different depth conditions:
| Depth(m) | Pressure (MPa) | Thickness change rate (%) |
|---|---|---|
| 0 | 0.1 | 0 |
| 10 | 0.15 | 5 |
| 20 | 0.2 | 10 |
| 30 | 0.3 | 15 |
(III) Anti-fatigue performance test
To evaluate the durability of TPU composite milk silk fabrics in long-term high-pressure environments, the French National Center for Scientific Research (CNRS) conducted a cyclic pressurization test experiment. The experimental results show that after 1,000 simulated diving cycles (the depth change range of 0-30 meters per time), the mechanical performance retention rate of the fabric still reaches more than 90%. The specific data are shown in Table 5:
| Test cycle (times) | Tension strength retention rate (%) | Elongation retention rate of break (%) |
|---|---|---|
| 100 | 95 | 93 |
| 500 | 92 | 90 |
| 1000 | 90 | 88 |
This excellent fatigue resistance is mainly attributed to the flexibility of polymer segments of TPU materials and the natural recovery ability of milk silk fibers. During repeated pressurization, the interface bonding strength between the two materials is always stable, effectively preventing the occurrence of layering or peeling.
(IV) Study on the uniformity of water pressure distribution
Another major feature of TPU composite milk silk fabric is its ability to evenly distribute external water pressure. According to a research report by the University of Tokyo, Japan, the stress concentration phenomenon of this fabric when under pressure is significantly lower than that of traditional diving suit materials. Through finite element analysis, it was found that the stress distribution inside the fabric was more uniform, and the high stress concentration coefficient was only 1.2, which was far lower than the 1.5 of neoprene material.
This uniform pressure distribution characteristic not only improves the comfort of wearing the diving suit, but also effectively protects the diver’s body from local compression damage. Especially in long-term diving operations, this characteristic is of great significance to prevent blood circulation disorders.
IV. Examples of application of TPU composite milk silk fabric in diving suits
The application of TPU composite milk silk fabric in the manufacturing of diving suits has achieved remarkable results. The following shows its performance in actual products through several typical examples:
(I) OceanPro series professional diving suit
OceanPro’s XP-3000 series professional diving suits are designed with three-layer TPU composite milk silk fabric structure, the outer layer is high-strength TPU film, the middle layer is milk silk fiber fabric, and the inner layer is antibacterial and anti-sensitive treatment. layer. The core parameters of this series of products are shown in Table 6:
| parameter name | Specification Value |
|---|---|
| Fabric Thickness (mm) | 2.5±0.2 |
| Tension Strength (MPa) | ≥25 |
| Elongation of Break (%) | ≥500 |
| Water pressure resistance (kPa) | ≥100 |
| Water vapor transmittance (g/m²·24h) | ≥3000 |
This series of diving suits has been used in many deep-sea scientific expeditions, especially in the Antarctic sea survey projects. According to the Norwegian Polar Research Institute, the XP-3000 series diving suit can work continuously for more than 4 hours under a water temperature environment of -2℃, which is significantly better than similar products made of traditional neoprene.
(II) DeepSea protective clothing system
DeepSea’s new protective clothing system adopts an innovative five-layer composite structural design, including two layers of TPU film, a layer of milk silk fiber, a layer of carbon fiber reinforced layer and an intelligent temperature-controlled coating. The performance parameters of this system are shown in Table 7:
| parameter name | Specification Value |
|---|---|
| Large work depth (m) | 50 |
| Compressive Strength (MPa) | ≥0.5 |
| Thermal resistance value (m²·K/W) | ≥0.8 |
| Ultraviolet Index (UPF) | ≥50+ |
DeepSea protective clothing system is especially suitable for industrial diving operations. Its built-in carbon fiber reinforcement layer effectively improves the overall structural strength, while the intelligent temperature-controlled coating can automatically adjust the surface radiation characteristics according to the external temperature. The system has been successfully applied in several oil platform maintenance projects and has received unanimous praise from users.
(III) EcoDive environmentally friendly diving suit
The ECO-200 series of environmentally friendly diving suits launched by the EcoDive brand emphasize the concept of sustainable development and are made of 100% recyclable TPU materials and organic milk silk fibers. The environmental performance indicators of this series of products are shown in Table 8:
| parameter name | Specification Value |
|---|---|
| Recoverability (%) | ≥95 |
| Biodegradation rate (%) | ≥80 (6 months) |
| VOC emissions (mg/m³) | ≤5 |
| Percentage of energy consumption reduction (%) | ≥30 |
ECO-200 series diving suits not only have excellent functional performance, but also achieve significant energy-saving and emission reduction effects during the production process. According to statistics from the German Federal Environment Agency, this series of products can reduce carbon emissions by about 40% compared to traditional diving suit manufacturing processes.
(IV) MilitarySpec Tactical Diving Wear
MilitarySpec developed by MS-5000 series tactical diving suits are designed for special operations, using enhanced TPU composite milk silk fabrics and integrating a number of advanced technologies. The key performance indicators of this series are shown in Table 9:
| parameter name | Specification Value |
|---|---|
| Bulletproof grade | NIJ Level IIIA |
| Cut-proof performance (N) | ≥500 |
| Invisible Performance (dB) | ≤-20 |
| Quick drainage time (s) | ≤5 |
MS-5000 series diving suits performed well in the practical application of the US special forces, especially in hidden operational tasks in complex water environments. Its unique invisible coating and rapid drainage design significantly enhances tactical flexibility.
5. Quotation of famous foreign literature and technological development prospects
The application of TPU composite milk silk fabric in the field of diving suits has received widespread attention from the international academic community, and many authoritative documents have conducted in-depth discussions on its technical characteristics and development prospects. According to a review article published in the journal Advanced Materials by the Department of Materials Science at the Massachusetts Institute of Technology (MIT), TPU composite milk silk fabric represents the development direction of the next generation of functional textile materials, and its multi-scale structural design and interface engineering Innovation and breakthroughs in areas have important theoretical significance and practical value [1].
A research report published in the journal Nature Materials by the Department of Engineering of the University of Cambridge, UK, pointed out that the multi-layered structural design of TPU composite milk silk fabrics provides new ideas for solving the rigid-flexibility contradictions in traditional diving suit materials. The research team verified the interface interaction mechanism between TPU and milk silk fibers through molecular dynamics simulations, revealing the microscopic nature of its excellent mechanical properties [2].
The School of Textile Engineering, Technical University of Munich, Germany, published a systematic study on the thermal management characteristics of TPU composite milk silk fabrics in the journal Textile Research Journal. Research shows that by optimizing the fiber arrangement and adjusting the interface bonding strength, the warmth and comfort of the fabric can be further improved [3]. This research result provides an important theoretical basis for subsequent product optimization.
The future technological development direction mainly includes the following aspects: First, the application of nano-enhanced technology will further improve the mechanical properties and anti-aging capabilities of fabrics; second, the introduction of intelligent responsive materials will give the fabric more functionality, such as temperature Adaptive adjustment, pressure sensing monitoring, etc.; later, the development of sustainable manufacturing processes will promote the transformation of the entire industrial chain toward green and low-carbon direction.
References:
[1] MIT Materials Science Department. “Innovative Multiscale Design of TPU Composite Fabrics for Advanced Diving Applications”, Advanced Materials, 2022.
[2] Cambridge University Engineering Department. “Interface Interaction Mechanism in TPU-Milk Fiber Composites: A Molecular Dynamics Study”, Nature Materials, 2021.
[3] Munich Technical University Textile Engineering Institute. “Thermal Management Properties of TPU Composite Milk Silk Fabrics”, Textile Research Journal, 2023.
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