Analysis of Infrared Camouflage Fabric Patent Technologies
Jun 25, 2024
Use of Infrared-Blocking Coatings
Coating fabrics with low emissivity coatings directly onto their surfaces is a straightforward and widely adopted method for manufacturing infrared camouflage fabrics. The principle behind this approach is that higher reflectance leads to lower emissivity. Therefore, materials with high reflectance, such as aluminum powder, are commonly used in the production of infrared-blocking coatings. However, incorporating aluminum flakes can enhance reflectance in visible light, which compromises camouflage effectiveness in visible spectra. Additionally, aluminum is susceptible to oxidation in the air, which significantly increases its emissivity, thereby reducing the effectiveness of the infrared camouflage.
introduces a brown-colored infrared low emissivity plate-like pigment coated with a dense ferric oxide layer on the surface of aluminum flakes. This innovation addresses the oxidation issue of aluminum powder, alters its gloss and color under visible light, and reduces its reflectance in visible light. The resulting infrared-blocking pigment achieves low infrared emissivity (wavelength 8-14 μm, emissivity 0.50-0.65) without metallic luster;
Do not use double sided tape to attach light panels to dusty, damp, wallpapered or uneven surfaces such as brick, unfinished wood or rough concrete walls;discloses an integrated infrared and radar stealth fabric. The infrared stealth layer consists of an infrared stealth coating and magnetron sputtered ITO film composite on its surface. The infrared stealth coating is composed of a film-forming agent, reflective filler, and solvent, where the reflective filler includes ITO, aluminum powder, and zinc oxide;
presents a high-spectral stealth camouflage coating using doped semiconductor material tin-doped indium oxide (GAZO) and quartz powder as auxiliary fillers. This coating exhibits low spectral emissivity and excellent high-spectral stealth performance;
uses glass microspheres mixed with microcapsule phase-change materials to create a coating with a low emissivity surface, where different parts of the coating exhibit varying emissivity characteristics. This combination of a low emissivity surface and uneven emission characteristics effectively achieves thermal infrared stealth camouflage. Phase-change energy storage materials in microcapsules primarily include tetradecane, octadecane, paraffin, and expanded graphite.
utilizes gallium (Ga), aluminum (Al), gallium oxide (Ga2O3), aluminum oxide (Al2O3), and zinc oxide (ZnO) to prepare nano-sized GAZO powder, further processed into low emissivity nano-coatings. These coatings can be applied to woven fabrics, knitted fabrics, non-woven fabrics, or synthetic leather surfaces via digital printing, screen printing, scraping, spraying, or immersion rolling. After drying or hot pressing, they form fabrics with infrared stealth capabilities suitable for making thermal infrared camouflage clothing, camouflage nets, and tents. They maintain the physical and chemical properties of the original products and are compatible with visible light, near-infrared (wavelength 0.38-2.5 μm), and infrared (wavelength 8-14 μm) multi-spectral stealth without compromising comfort when worn.
introduces an infrared stealth coating using three different phase-change materials with varying phase-change temperature ranges as core materials encapsulated with melamine-formaldehyde resin as wall materials. These microcapsules are added to infrared stealth coatings via in-situ polymerization to serve as temperature control materials, adjusting emissivity to achieve infrared camouflage effects within a temperature range of approximately 10-60°C. This coating overcomes the challenges of low emissivity infrared stealth materials being incompatible with visible light and radar bands, poor tolerance to pollution, and susceptibility to increased emissivity from dust and moisture, which reduce stealth effectiveness.
Use of Compound Dyes
Using infrared-blocking coatings does not require extensive consideration of the material surface of the object being camouflaged, making it a widely adopted and straightforward method. However, clothing performance deteriorates after coating due to reduced moisture absorption, breathability, water resistance, and softness of the fabric. Consequently, researchers have explored using dyes to achieve near-infrared camouflage for military clothing. This method involves selecting dyes with similar or identical infrared reflectance to the surrounding environment, thereby achieving counter-surveillance against infrared instruments.
Deep green and Sulphur yellow RK dyes have reflectance rates of 78% to 84% (700-1200 nm) and 14% to 65% (700-1200 nm), respectively, at concentrations of 10 g/kg and 15 g/kg. By combining these dyes, a deep green color with a reflectance rate of 35% to 70% (700-1200 nm) can be achieved. Additionally, carbon black, which has infrared absorption capability, can be added to further reduce the reflectance of the dyes to meet requirements.
combines suitable vat dyes and incorporates a coating like K-FFB that effectively adjusts the fabric's near-infrared reflectance spectrum to closely match the background. This approach enhances the fabric's integration into the environment without compromising garment performance.
introduces camouflage protective fabrics with a phthalocyanine dye pattern layer known for excellent near-infrared absorption properties. Experimental results indicate optimal infrared absorption when this dye is combined with cotton fabrics.
details a dyeing process for camouflage tent fabrics using disperse dyes with near-infrared shielding functions and UV absorbers. This process ensures the fabric has good near-infrared green shielding capability and lightfastness.
describes a method for producing military-grade far-infrared camouflage clothing, selecting disperse dyes and vat dyes during the printing process based on the spectral reflectance values specified in camouflage fabric standards. This ensures the fabrics meet infrared camouflage requirements.
outlines a processing method for polyester infrared camouflage printed tapes, using polyester as the raw material and dyeing it with dyes that have similar or identical infrared reflectance to the surrounding environment. The combination of Eriochrome Black, disperse dyes, and a small amount of coating achieves the desired effect through extensive testing.
utilizes disperse dyes, vat dyes, and infrared-blocking agents to produce multifunctional infrared camouflage fabrics with stable infrared reflectance, low cost, and primarily environmentally friendly dyes.
These approaches demonstrate diverse strategies using compound dyes to achieve effective infrared camouflage while addressing the performance trade-offs associated with coatings. Each method seeks to balance camouflage effectiveness with practical garment properties like comfort and durability.
Conclusion:
The analysis of Chinese patents on infrared camouflage fabric technologies reveals that current production techniques predominantly involve basic methods such as coating with infrared-resistant compounds and dye combinations. There remains significant room for improvement in simplifying manufacturing processes, enhancing fiber modification, and increasing the durability of infrared camouflage effects.
Furthermore, the performance requirements for infrared camouflage fabrics continue to escalate with advancements in technology. For instance, the application of more advanced or broader-spectrum infrared detection technologies in military settings imposes higher demands on the infrared resistance capabilities of camouflage fabrics. Therefore, there exists substantial long-term demand and extensive research and development opportunities in the field of infrared camouflage fabrics.
