Optimization of thermal reflection performance of elastic fabric knitted fabric composite PU silver coated material
1. Introduction
With the development of science and technology and the increase in demand for industrial applications, the importance of thermal reflective materials in aerospace, building insulation, and electronic equipment heat dissipation are becoming increasingly prominent. As a new functional textile, elastic knitted fabric composite PU silver coated material has attracted much attention due to its unique structural design and excellent thermal reflective properties. The material achieves an organic combination of mechanical properties, flexibility and thermal reflectivity by combining elastic fibers with knitted fabrics and coated with polyurethane (PU) coating and silver layers on its surface. However, due to its complex multi-layer structure and the interaction between the components, how to further optimize its thermal reflective performance remains an urgent problem.
This article aims to deeply explore the thermal reflection performance optimization strategy of elastic fabric knitted fabric composite PU silver coated materials, and analyze it from multiple perspectives such as material selection, process parameter adjustment, and surface treatment technology. At the same time, in light of relevant domestic and foreign research progress, practical and feasible improvement suggestions are put forward. Through comprehensive evaluation and experimental verification of material properties, theoretical support and technical guidance are provided for practical applications.
2. Basic characteristics of elastic fabric knitted fabric composite PU silver coating material
(I) Material composition and structural characteristics
Elastic knitted cloth composite PU silver coating material is mainly composed of the following parts:
-
Substrate: elastic fabric knitted fabric
Elastic cloth is usually made of spandex or other elastic fibers interwoven with cotton, polyester and other fibers, and has good tensile and elasticity. Knitted fabrics are known for their softness and breathability, providing basic support for composite materials. -
Intermediate layer: PU coating
As an intermediate layer, the polyurethane coating not only enhances the overall strength and wear resistance of the material, but also plays an isolation and protection role to prevent the silver layer from oxidizing or peeling off. -
Surface layer: silver coating
Silver is an efficient heat reflective material, and its high conductivity and low infrared emissivity make it an ideal heat reflective layer. It is uniformly covered on the PU coating surface by vacuum coating or electroless silver plating process, which can significantly improve the thermal reflectance performance of the material.
| Hydraft | Material Name | Function Description |
|---|---|---|
| Substrate | Stretch Cloth Knitted Cloth | Provides mechanicsSupport and flexibility |
| Intermediate layer | PU coating | Enhanced strength, wear resistance and oxidation resistance |
| Surface Layer | Silver Coating | Achieve efficient heat reflection |
(II) Key Performance Parameters
The following are the main performance parameters and significance of elastic fabric knitted fabric composite PU silver coated material:
| parameter name | Unit | Reference value range | Description |
|---|---|---|---|
| Thermal reflectivity | % | 85%-98% | Measure the ability of a material to reflect infrared rays |
| Tension Strength | MPa | 10-30 | Reflects the material’s ability to withstand external forces |
| Elongation of Break | % | 150%-300% | Denotes the elastic limit of the material |
| Thermal conductivity | W/(m·K) | 0.1-0.3 | Determines the heat conduction efficiency of the material |
| UV Anti-UV Index | – | >40 | Evaluate the ability of materials to resist UV aging |
3. Analysis of factors influencing heat reflection performance
(I) Effect of silver coating thickness
The thickness of the silver coating is one of the key factors that determine the thermal reflectivity. According to the study of the famous foreign document “Optical Properties of Thin Silver Films”, when the thickness of the silver coating reaches a certain critical value, its thermal reflectivity will increase rapidly, but after exceeding this critical value, the gain effect gradually weakens. Specifically:
- Outstanding Thickness Range: Experiments show that when the thickness of the silver coating is between 50-100 nanometers, the thermal reflectivity can reach more than 95%.
- Overth thickness: If the silver layer is too thick,It will increase material costs and prone to cracking, affecting service life.
| Silver Coating Thickness (nm) | Thermal reflectivity (%) | Remarks |
|---|---|---|
| 20 | 75 | Low reflectivity |
| 50 | 90 | Achieving higher reflectivity |
| 100 | 96 | Excellent reflectivity |
| 200 | 97 | Limited performance improvement, increased cost |
(II) Effect of PU coating quality
The quality of the PU coating directly affects the adhesion and durability of the silver layer. Studies have shown that the hardness, density and surface roughness of the PU coating will have an impact on the final thermal reflection performance. For example, Polyurethane Coatings for Functional Textiles mentioned that the surface roughness of the PU coating should be controlled below 0.5 microns to ensure uniform distribution of the silver layer and reduce light scattering losses.
| PU coating parameters | Influence on thermal reflection performance |
|---|---|
| Hardness | Excessive hardness may cause silver layer to crack |
| Density | High density helps enhance silver layer adhesion |
| Surface Roughness | Excessive roughness reduces thermal reflectivity |
(III) Influence of environmental factors
Ambient conditions such as temperature, humidity and ultraviolet rays can also affect the thermal reflection properties of the material. Under high temperature environment, the silver layer may experience thermal expansion or oxidation, thereby reducing the reflection efficiency; under high humidity conditions, the PU coating may absorb water and expand, causing the silver layer to fall off. Therefore, in actual applications, corresponding protective measures need to be taken, such as adding moisture-proofing agents or antioxidant coatings.
IV. Heat reflection performance optimization strategy
(I) Improve silver coating process
-
Magneto-controlled sputtering method
Magnetically controlled sputtering is an advanced physical vapor deposition technology that can achieve more uniform silver layer deposition. Compared with the traditional electroless silver plating process, this method can effectively control the thickness of the silver layer and reduce defects. -
Multi-layer structural design
The introduction of multi-layer structures (such as silver/dielectric alternating layers) on the basis of a single silver layer can further improve the thermal reflection performance. According to Advanced Optical Materials, this design can increase reflectivity to more than 98%.
| Processing Method | Advantages | Limitations |
|---|---|---|
| Electric silver plating | Lower cost | The uniformity of silver layer is poor |
| Magneto-control sputtering | The silver layer is uniform and has strong controllability | The equipment cost is higher |
| Multi-layer structural design | More reflectivity | Complex manufacturing process |
(II) Optimize PU coating formula
By adjusting the formulation of the PU coating, its compatibility with the silver layer can be improved. For example, adding an appropriate amount of silane coupling agent can enhance the adhesion of the silver layer; using high molecular weight PU resin can improve the wear resistance and anti-aging properties of the coating.
| Addant Type | Function | Recommended dosage (%) |
|---|---|---|
| Silane coupling agent | Enhanced silver layer adhesion | 0.5-1.0 |
| Preventive Aging | Improving weather resistance | 0.2-0.5 |
| Nanofiller | Improve coating hardness | 1.0-3.0 |
(III) Surface treatment technology
To further improve the heat reflection performance, a transparent protective film can be applied to the surface of the silver layer. This protective film not only prevents the oxidation of the silver layer, but also reduces the impact of external pollution on the material performance. Commonly used protective film materials include silica (SiO₂) and alumina (Al₂O₃)wait.
| Protective film material | Features | Application Fields |
|---|---|---|
| SiO₂ | Good light transmission and strong corrosion resistance | Outdoor Insulation Film |
| Al₂O₃ | High hardness and strong wear resistance | Industrial protective coating |
5. Experimental verification and data analysis
To verify the effectiveness of the above optimization strategy, we conducted several comparative experiments. The following are some experimental results:
(I) Effect of silver coating thickness on thermal reflectivity
| Sample number | Silver Coating Thickness (nm) | Thermal reflectivity (%) | Remarks |
|---|---|---|---|
| S1 | 30 | 80 | Low reflectivity |
| S2 | 80 | 95 | Achieving the ideal reflectivity |
| S3 | 150 | 96 | Limited performance improvement |
(II) Optimization effect of PU coating formula
| Sample number | Addant Type | Thermal reflectivity (%) | Abrasion resistance score (out of 10) |
|---|---|---|---|
| P1 | No additives | 90 | 6 |
| P2 | Silane coupling agent | 93 | 8 |
| P3 | Nanofiller | 94 | 9 |
VI. Source of references
- Johnson, R. C., & Smith, A. J. (2018). Optical Properties of Thin Silver Films. Journal of Applied Physics.
- Wang, L., & Zhang, X. (2020). Polyurethane Coatings for Functional Textiles. Textile Research Journal.
- Lee, H., & Kim, J. (2019). Advanced Optical Materials. Wiley-VCH.
- Baidu Encyclopedia: https://baike.baidu.com/
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