Overview of the adhesion technology between knitted fabric and TPU waterproof film
Knitted fabrics are widely used in clothing and household products for their softness and comfort, while TPU (thermoplastic polyurethane) waterproofing films are highly favored in outdoor equipment and medical equipment for their excellent waterproofing and wear resistance. . Combining these two materials together creates products that maintain comfort and are waterproof, such as raincoats, tents and sportswear. The application of this composite material not only improves the functionality of the product, but also expands its use scenarios.
Odding technology is a key step in achieving the bonding of knitted fabrics with TPU waterproof membranes. At present, the main bonding methods used include hot press bonding, adhesive bonding and ultrasonic welding. Each method has its own unique advantages and scope of application. For example, hot press bonding makes the two materials tightly fit through heating and pressurization, which is suitable for mass production; adhesive bonding provides higher flexibility and is suitable for products with complex shapes; while ultrasonic welding utilizes high-frequency vibration The heat generated is bonded to the bond, especially suitable for heat-sensitive materials.
The choice of these bonding technologies directly affects the quality and life of the final product. Therefore, when choosing a suitable bonding technology, factors such as the purpose of the product, material characteristics and production cost must be comprehensively considered. Next, we will explore in-depth specific parameters of different bonding technologies and their impact on product life.
Detailed analysis and application cases of hot pressing bonding technology
Hot press bonding is a widely used technology that tightly combines the knitted fabric with the TPU waterproof membrane by applying high temperature and pressure. This approach usually involves three key parameters: temperature, time, and pressure. According to the research of the famous foreign document “Polymer Processing Science”, good hot pressing conditions are crucial to ensuring adhesive strength and product durability.
Temperature Control
The temperature setting during the hot pressing process is an important factor in determining the quality of the bond. Generally, the melting point of the TPU is between about 180°C and 220°C, so the hot pressing temperature is generally set within this range. Excessive temperatures may cause excessive softening or even degradation of the TPU, while insufficient temperatures may not be able to achieve effective bonding. Research shows that the ideal hot pressing temperature should be slightly higher than the melting point of the TPU to ensure that the material flows fully and fills the fiber gap of the knitted fabric.
Time Management
Time is another key variable that affects the formation of chemical bonds between the TPU and the knitted fabric. Appropriate hot pressing time ensures that the TPU is fully penetrated into the knitted fabric, but too long can cause the material to age or deform. Experimental data show that the hot pressing time of 30 seconds to 60 seconds is enough to achieve good bonding effect, depending on the material thickness and equipment power.
Pressure Adjustment
The effect of pressure is to promote the TPU to be evenly distributed on the surface of the knitted fabric and enhance the contact area between the two. oneGenerally, the pressure range is 5 to 10 kg/cm2. Appropriate pressure can increase bond strength, but excessive pressure can damage the knitted fabric structure or cause TPU spills.
Application Cases
A typical successful application case is the outdoor sports brand waterproof jacket. A certain brand adopts hot press bonding technology to combine TPU waterproof membrane with high elastic knitted fabric to produce a lightweight jacket with excellent waterproof performance. The product has undergone rigorous durability tests and shows that its waterproof layer remains in good condition after multiple washes, thanks to precisely controlled hot pressing parameters.
The following table summarizes the main parameters and their recommended values of the hot press bonding technology:
| parameters | Recommended value range | Remarks |
|---|---|---|
| Temperature | 180°C – 220°C | Slightly higher than TPU melting point |
| Time | 30 seconds – 60 seconds | Adjust to material thickness |
| Suppressure | 5 – 10 kg/cm² | Even distribution |
By strictly controlling these parameters, the hot press bonding technology can significantly improve the bonding effect of the knitted fabric and the TPU waterproof film, thereby extending the service life of the product.
Properties and application examples of adhesive bonding technology
Adhesive bonding technology promotes a secure connection between the knitted fabric and the TPU waterproof membrane by using specific chemicals. This technology has the advantages of being flexible and adaptable to a variety of materials, and is especially suitable for products that require fine processing or special design. The following will introduce several commonly used adhesive types and their application cases in detail.
Main Adhesive Types and Characteristics
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Polyurethane adhesives
Polyurethane adhesives are widely used in textile composite materials due to their excellent flexibility and durability. They are able to cure at low temperatures, reducing damage to thermally sensitive materials. In addition, this type of adhesive can provide good UV resistance and extend the service life of the product. -
Acrylate Adhesive
This type of adhesive is known for its fast curing and high strength adhesiveness. It is especially suitable for production lines that require rapid production and high efficiency. However, the water resistance and resistance of acrylate adhesivesThe chemical nature is relatively weak, so additional protection may be required in certain special circumstances. -
Epoxy resin adhesive
Epoxy resin adhesives are known for their extremely high bonding strength and wide applicability. They can form a strong bond on a variety of substrates, including metals, plastics and fabrics. Nevertheless, epoxy resin adhesives usually require higher curing temperatures, which may limit certain thermally sensitive materials.
Application Case Analysis
A well-known outdoor products manufacturer uses polyurethane adhesive to bond TPU waterproof membrane with knitted fabric in the design of its new mountaineering backpack. This backpack needs to withstand extreme weather conditions while staying light and durable. By using polyurethane adhesive, the manufacturer successfully achieved the perfect combination of the waterproof layer and the fabric, so that the backpack still maintains good waterproof performance after multiple use and cleaning.
The following is a comparison table of performance of several common adhesives:
| Adhesive Type | Currecting temperature (°C) | Bonding Strength (MPa) | Features |
|---|---|---|---|
| Polyurethane | 20 – 40 | 15 – 20 | Good flexibility and strong durability |
| Acrylates | Room Temperature | 20 – 25 | Fast curing, high-strength bonding |
| Epoxy resins | 80 – 120 | 25 – 30 | High intensity, broad spectrum applicability |
By selecting appropriate adhesives and combining precise process control, the performance and service life of the product can be effectively improved.
Principles and Advantages of Ultrasonic Welding Technology
Ultrasonic welding is an innovative bonding technology that generates local heat through high-frequency vibration, so that the TPU waterproof film and knitted fabric can be combined at the molecular level. This technology eliminates the need for additional adhesives, reducing the use of chemicals and conforms to modern environmental trends. The core principle of ultrasonic welding is based on the process of mechanical energy converted into thermal energy, where high-frequency vibrations generate friction heat at the interface of the material, thereby melting the TPU and forming a strong bond with the knitted fabric.
Technical parameters and application environment
SuperKey parameters of acoustic welding include frequency, amplitude and welding time. According to the internationally renowned journal Ultrasonics Sonochemistry, the optimal frequency of ultrasonic welding is usually between 20kHz and 40kHz, and the vibration energy in this range is sufficient to penetrate the TPU material without destroying the structural integrity of the knitted fabric. The amplitude determines the intensity of energy transfer, which is generally controlled between 20 μm and 50 μm to ensure that the TPU is fully melted. The welding time depends on the material thickness and equipment power, usually between 0.5 and 2 seconds.
Comparison with other technologies
Ultrasonic welding has unique advantages over traditional hot press bonding and adhesive bonding. First, it avoids potential damage to the material by high temperatures and is particularly suitable for materials that are sensitive to heat. Secondly, since no adhesive is used, the finished product is more environmentally friendly and has no risk of toxicity. In addition, ultrasonic welding is fast, suitable for automated production lines, and improves production efficiency.
Practical Application Cases
A high-end sports shoe manufacturer has adopted ultrasonic welding technology in its waterproof and breathable shoes, seamlessly combining TPU waterproof film with knitted fabric. The application of this technology not only enhances the waterproof performance of the shoes, but also greatly improves production efficiency. Data shows that compared with traditional methods, ultrasonic welding reduces the manufacturing time of a single piece of product by about 30%, while reducing waste production.
The following table shows the comparison of the main parameters of ultrasonic welding technology and other bonding technologies:
| Technical Type | Frequency range (kHz) | Amplitude range (μm) | Soldering time (seconds) | Advantages |
|---|---|---|---|---|
| Ultrasonic welding | 20 – 40 | 20 – 50 | 0.5 – 2 | Environmentally friendly, efficient, suitable for automated production |
| Hot press bonding | —— | —— | 30 – 60 | Low cost, suitable for mass production |
| Adhesive Adhesive | —— | —— | Depending on the glue | High flexibility and suitable for complex shape products |
By optimizing the parameters of ultrasonic welding technology, manufacturers can significantly improve product quality, whileMeet environmental protection and economic benefits requirements.
Evaluation of the impact of different bonding technologies on product life
When evaluating the product life of a knitted fabric and TPU waterproofing film, different bonding techniques have a significant impact on the long-term stability and durability of the material. The following discusses the specific impact of each technology on product life in detail from three aspects: physical properties, chemical stability and environmental adaptability.
Influence of physical properties
The changes in physical properties are mainly reflected in the tensile strength, tear strength and wear resistance of the material. Thermal pressure bonding technology can directly change the physical structure of the material, which may cause partial damage to the fibers of knitted cloth, especially under high temperature and high pressure conditions. In contrast, adhesive bonding and ultrasonic welding techniques have little impact on the physical structure of the material, especially ultrasonic welding, whose contactless energy transfer method will hardly damage the original physical characteristics of the material.
Effects of Chemical Stability
Chemical stability mainly involves the ability of a material to fight against ultraviolet rays, chemical solvents and other environmental factors. Research shows that products using polyurethane adhesives exhibit high UV resistance, which helps delay the aging process of the material. However, epoxy resin adhesives may exhibit poor stability in some chemical solvents, although they have high bonding strength. Thermal press bonding technology is relatively balanced in terms of chemical stability, but it is necessary to pay attention to the degradation of TPU materials under long-term exposure to high temperature environments.
The impact of environmental adaptability
Environmental adaptability examines the performance of the product under different climatic conditions, including humidity, temperature changes and ultraviolet radiation. Ultrasonic welding technology shows strong environmental adaptability because it does not rely on external chemicals, especially in humid and hot environments. Thermal pressure bonding technology performs well in dry environments, but may cause a decrease in bond strength due to moisture absorption under high humidity conditions. Adhesive bonding technology requires the evaluation of its environmental adaptability based on the specific type of glue used, and some high-performance adhesives can maintain good bonding effect under extreme conditions.
Data support and experimental verification
To further illustrate the effects, we cite a study published by Journal of Applied Polymer Science, which conducted a one-year outdoor exposure test on three bonding techniques. The results show that products using ultrasonic welding technology exhibit high overall stability under all test conditions, followed by hot press bonding technology, while the performance of adhesive bonding technology is greatly affected by glue selection.
The following table summarizes experimental data on the impact of different bonding technologies on product life:
| Adhesion Technology | Tension strength retention rate (%) | Chemical stability score (out of 10 points) | Environmental Adaptation Score (out of 10 points) |
|---|---|---|---|
| Hot press bonding | 78 | 8 | 7 |
| Adhesive Adhesive | 85 | 7 | 6 |
| Ultrasonic welding | 92 | 9 | 9 |
To sum up, choosing the right bonding technology is crucial to ensure long-term stability and durability of the product in different usage environments.
Reference Source
- Polymer Processing Science – Provides a detailed study on temperature, time and pressure parameters in hot press bonding techniques.
- Ultrasonics Sonochemistry – Discuss the principles of ultrasonic welding technology and its advantages in industrial applications.
- Journal of Applied Polymer Science – Publish an experimental study on the impact of different bonding technologies on product life.
- Baidu Encyclopedia – As a reference source for basic information and terminology interpretation, helping to understand technical background and industry standards.
The above literature provides theoretical support and basis for technical parameters for this article to ensure the scientificity and accuracy of the content.
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