In response to escalating climate challenges, thermal insulation coatings have become a beacon of innovation in the textile industry. Silica aerogel is a nanoscale miracle. It has become a key player, transforming fabrics with unparalleled heat resistance. Meanwhile, silica’s powerful capabilities also extend to waterproof coatings. It provides solutions beyond traditional limitations. Let’s dive into the capabilities of silica in reinforcing fabrics. At the same time, it also opened up new possibilities and transformative aspects of textile applications.
1. Silica used in thermal insulation coatings
In recent years, the earth’s climate has deteriorated abnormally. Extreme temperatures occur frequently around the world in summer. This has adversely affected all aspects of people’s lives and productivity. To mitigate these impacts, heat-insulating coating fabrics have emerged in the textile industry. The so-called thermal insulation coating fabric refers to coating with a thermal insulation function. They are suitable for use on fabric surfaces. This coating reduces the internal temperature of the fabric covering. It also reduces energy consumption by blocking, reflecting, or radiating solar energy. It has the advantage of consuming minimal energy while achieving effective thermal insulation. These fabrics present promising applications in a world of scarce resources.
Silica aerogel is an amorphous nanoscale porous material. It has a controllable structure of nanoporous network and gas dispersion medium filling pores. Its density is adjustable between 3 and 500 mg/cubic centimeter, making it the world’s lowest-density solid material. Its porosity ranges from 80% to 99.8%, and pore sizes fall between 1 to 100 nm, providing a surface area of up to 1000 m²/g. Due to its unique nanopore structure, silica aerogel exhibits the lowest thermal conductivity. It reaches 0.017 W/(m·K) at normal temperature and pressure. It has the lowest thermal conductivity of any known solid material. So, it holds immense potential in the field of heat insulation research.
Conventional preparation methods use silicates or colloidal silica as silicon precursors. Wet gels were prepared using the sol-gel method. Then perform aging and solvent replacement treatments. The next normal pressure drying process removes the liquid medium from the wet gel pores. Thus, a structurally complete silica aerogel is formed. Yet, the wet gel has hydrophilic -OH groups on its surface, so it needs to be dried under normal pressure. It can cause significant shrinkage stress on porous structures. This often results in gel shrinkage and fragmentation of the silica aerogel. Eventually, it becomes hydrophilic, to absorb water easily during application or later use. If you want to overcome this problem. Hydrophobic surface modification must be carried out before normal pressure drying. This prevents damage to the hole structure during machining.
According to statistics, the global market has a compound annual growth rate of 36.4% in recent years. Among them, the compound annual growth rate of the Chinese market reached 61.1%. Silica aerogels can reduce the weight of thermal protective clothing. It also significantly reduces losses during use. For example, a specific proportion of silica aerogel can be added to a PA or PU adhesive (in film labels, we also use barium sulfate to produce masterbatch as an additive, please check it here). Then it applies the thermal insulation coating agent directly to the cotton fabric.
SiO2 aerogel has the characteristics of high porosity and low thermal conductivity. So it becomes a new type of super-insulating material. But, SiO2 aerogel has poor flexibility and integrity. Besides, it has high thermal conductivity. These limit the application of SiO2 aerogel. But, composite insulation solves these problems. That is to use in-situ sol-gel and compression molding methods. This method increases the flexibility, integrity, and high-temperature insulation properties of the fabric. This reinforcement effect makes silica aerogel an independent block thermal insulation material. Promote the widespread use of thermal insulation coating fabrics in the textile industry.
2. Silica used in waterproof coatings
Traditional fabrics tend to become wet upon contact with water. So, the application of silicon dioxide in fabric coatings offers a solution to this issue. It provides textiles with hydrophobic and waterproof properties. Nano-coatings can make textiles of various materials waterproof. And it won’t change its appearance or texture. These nanocoatings are colorless and transparent. Not only does it keep the fabric breathable, but it also provides long-lasting waterproofing and prevents leaks.
The process involves applying nanocoatings to fabrics, allowing them to repel water effectively. The nanocoating is invisible and does not affect the fabric’s texture or appearance. To prove the effectiveness of nanocoatings, we apply the coating to the surface of cotton fabric and then place it in water. Although cotton has a natural tendency to absorb water. The nano-coating makes the fabric buoyant, demonstrating its ability to repel water. Even after 12 hours in the water, the coated cotton fabric remained afloat. Later water droplet tests on the fabric surface confirmed its water-resistant properties.
The process of nanocoating is very simple. So, it is a feasible and effective method to enhance the waterproof performance of fabrics. The main ingredients of nanocoating are silica and alcohol. Both are commonly used in daily life. They are considered safe and environmentally friendly. Silica is a natural material. It can be used on glass, ceramics, and even children’s play sand. The nano-coating process shrinks the silica to nanoscale dimensions. So it can penetrate the fabric’s fibers without affecting breathability.
Nanocoating is an adverb. It works on a variety of textile materials including cotton, polyester, silk, leather, and wool. The process is simple, just spray, brush, or soak the fabric in the nanocoating solution. Once the fabric is wet, allow it to dry completely to form an effective nano-coating. The water-resistant properties of the nano-coated fabric simplify the cleaning process. So it is resistant to drinks, teas, soups, and even blood. These reduce the risk of contamination.
Nylon is known for its durability, abrasion resistance, and excellent tensile strength. It is a suitable candidate for waterproofing nano-coating. Nylon nano-coating testing proved its ability to effectively repel water and mud. The hydrophobic nature of the nanocoating prevents water from penetrating the fabric. This allows the mud to roll off the surface of the fabric. Additionally, the nanocoating is resistant to oil molecules in the air. It ensures that any oil-based stains are washed away easily, keeping nylon fabrics clean.
In the end, we can use a certain proportion of silica in waterproof coatings. It provides an effective solution to the waterproofing problem of textiles. This technology not only improves the functionality of the fabric. It also opens up possibilities for creative applications, for example floating mats. Nanocoatings are particularly safe and environmentally friendly. It is simple to apply and easy to operate. So silica nanocoating becomes a viable option for various textile materials. The lifespan and performance of waterproof fabrics are particularly
