Research on multi-layer composite technology of four-sided composite TPU fleece fabric

1. Introduction

As a new functional textile material, four-sided composite TPU fleece fabric has been widely used in sportswear, outdoor equipment and household goods in recent years. Its unique multi-layer composite structure imparts excellent elasticity, warmth and waterproof and breathable properties to the fabric, making it one of the important directions in modern textile development. With the continuous growth of global consumers’ demand for high-performance textiles, in-depth research on the multi-layer composite technology of four-sided elastic composite TPU fleece fabrics has important theoretical significance and practical application value.

This study aims to systematically explore the multi-layer composite technology principle and key technical parameters of four-sided elastic composite TPU fleece fabric. By analyzing the interaction mechanism between various functional layers, the key factors affecting the composite effect are revealed and optimization solutions are proposed. At the same time, this article will combine new research results at home and abroad to elaborate on the process flow and technical difficulties of this type of fabric in actual production, and provide reference for relevant enterprises and scientific researchers. In addition, this study will focus on how to improve the overall performance of fabrics by improving the composite process to meet the needs of different application scenarios.

2. Basic characteristics and structural characteristics of four-sided composite TPU fleece fabric

(I) Basic Features

Four-sided composite TPU fleece fabric is a high-performance textile material composed of multiple functional layers. Its core characteristics are mainly reflected in the following aspects:

1. Elasticity: Thanks to the special four-way stretching technology, the fabric has excellent elastic recovery ability in the horizontal, vertical and oblique directions, with an elongation rate of more than 200%, and many It can still maintain good dimensional stability after substretching.
2. Heatability: The fleece fiber layer is woven with microfibers, forming a large number of tiny air cavity, effectively blocking heat loss and giving the fabric excellent warmth.
3. Waterproof and breathable: The TPU film layer has a unique microporous structure that allows water vapor to pass through while preventing moisture from penetration, achieving an ideal moisture-heat balance effect.
4. Durability: The specially treated surface coating significantly improves the wear resistance and tear resistance of the fabric and extends its service life.

(Bi) Structural Characteristics

Four-sided composite TPU fleece fabric usually consists of the following layers:

1. External fabric layer: woven with high-strength polyester or nylon fiber, with excellent UV resistance and wind resistance.
2. TPU film layer: As the intermediate functional layer, it plays a key waterproof and breathable role, and the thickness is generally controlled between 0.05-0.1 mm.
3. Fleece Fleece Fleece Layer: The inner layer is made of soft and comfortable fleece material, providing excellent warmth and skin-friendly experience.
4. Adhesive layer: used to connect each functional layer to ensure the stability and durability of the composite structure.

This multi-level composite structure not only realizes the organic combination of various performances, but also provides broad space for subsequent functional modifications.

3. Principles and key technical parameters of multi-layer composite technology

(I) Principles of composite technology

The multi-layer composite process of four-sided elastic composite TPU fleece fabric involves the dual action mechanism of physicochemical. First, each functional layer is initially fixed by hot melt adhesive or aqueous polyurethane adhesive; second, a pressing treatment is carried out under specific temperature and pressure conditions to form a firm interface bonding force between molecules. In this process, the thermoplastic characteristics of the TPU film play an important role – under heating conditions, the TPU molecular chains soften and partially merge into the microstructure of adjacent layers, thus forming a stable three-dimensional network structure.

Study shows that the quality of the composite interface directly determines the overall performance of the finished fabric. According to Johnson et al. (2019), when the composite temperature is controlled within the range of 120-140°C, good interfacial binding strength can be obtained while avoiding functional layer damage caused by overheating (Johnson, S., et al., 2019). In addition, an appropriate pressurization time (usually 10-20 seconds) helps to improve recombination efficiency and reduce bubble residues.

(2) Key technical parameters

The successful implementation of multi-layer composite technology depends on the precise control of multiple key parameters, mainly including the following aspects:

1. Composite temperature: Directly affects the flowability of the TPU film and the activation degree of the adhesive. Too high or too low temperatures will reduce the compounding effect.
2. pressurization time: It needs to be adjusted according to the specific material characteristics, and it is usually recommended to control it within the range of 10-20 seconds.
3. Cooling Rate: Rapid cooling helps lock the composite structure, but too fast can lead to internal stress accumulation.
4. Adhesive coating amount: An appropriate amount of adhesive can ensure good interface bonding, and excessive amounts may affect the breathability of the fabric.

IV. Production process flow and technical difficulties

(I) Production process

The production of four-sided composite TPU fleece fabrics usually includes the following steps:

1. Pretreatment: Clean and dry the fabric substrate, remove surface impurities and adjust the moisture content.
2. Coating adhesive: Use anilox roller or spraying equipment to evenly apply the adhesive to ensure even coverage.
3. Composite Compression: stack each functional layer in the design order and then feed it into the composite machine, and complete the compression under the set temperature and pressure.
4. Cooling and Scaling: The cooling rollers quickly cool down to cure the composite structure.
5. After organizing: Perform functional treatments such as water splashing and anti-static as needed.

(II) Technical Difficulties

1. Interface combination problem: Because the materials of each functional layer vary greatly, layering is prone to occur. Solutions include optimizing the adhesive formulation and improving composite process conditions.
2. Breathability Control: The microporous structure of the TPU film may be closed under high temperature and high pressure, affecting the breathability performance. It can be improved by adjusting the composite parameters and selecting highly breathable TPU materials.
3. Dimensional stability: The thermal stress generated during the composite process may cause the fabric to shrink and deform. It is recommended to use pre-shrinkage and gradual heating to alleviate this problem.

5. Performance testing and evaluation methods

In order to comprehensively evaluate the comprehensive performance of four-sided composite TPU fleece fabrics, the following types of tests are usually required:

1. Mechanical performance test: Including indicators such as tensile strength, tear strength and elastic recovery rate, it is determined using ASTM or ISO standard methods.
2. Functional Test: Covering waterproofness, breathability and warmth, standard methods such as JIS L1092, BS 7209 and ISO 11092 are used respectively.
3. Comfort Evaluation: Evaluate the feel, breathability and sweating effect of the fabric through a combination of subjective scoring and objective measurement.

6. Citations and case analysis of famous foreign literature

(I) Literature Citation

1. Johnson, S., et al. (2019). “Optimization of TPU film lamination parameters for functional textiles.” Journal of Textile Engineering & Fibre Science, 47(3), 215-228 .

   • This study explores in detail the impact of key parameters such as temperature and pressure on interface binding strength during TPU film recombination, and proposes an optimization plan.

2. Lee, H., & Kim, J. (2021). “Advanced multi-layer composite technology for sportswear applications.” Textile Research Journal, 91(11-12), 1789-1802 .

   • The article introduces new progress in multi-layer composite technology in the field of sportswear, and emphasizes the balance between functionality and comfort.

3. Patel, R., et al. (2020). “Characterization of breathable waterproof fabrics using novel testing methods.” Materials Today Communications, 25, 101546.

   • A waterproof and breathable evaluation system based on new testing methods is proposed, providing an important reference for related research.

(II) Case Analysis

Taking a well-known German outdoor brand as an example, the four-sided composite TPU fleece jacket it launched uses advanced multi-layer composite technology, which achieves excellent waterproof and breathable performance and comfortable wearing experience by precisely controlling the composite parameters. The product has been widely praised after it was launched, fully demonstrating the practical application value of this technology.

Reference Source

1. Johnson, S., et al. (2019). “Optimization of TPU film lamination parameters for functional textiles.” Journal of Textile Engineering & Fibre Science, 47(3), 215-228.
2. Lee, H., & Kim, J. (2021). “Advanced multi-layer composite technology for sportswear applications.” Textile Research Journal, 91(11-12), 1789-1802 .
3. Patel, R., et al. (2020). “Characterization of breathable waterproof fabrics using novel testing methods.” Materials Today Communications, 25, 101546.
4. Baidu Encyclopedia. (2023). Four-sided composite TPU fleece fabric. [Online Resource]. https://baike.baidu.com/

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