What are the development trends of flame-retardant textiles?

Flame-retardant textiles refer to fabrics with flame-retardant properties made by fixing flame retardants onto fibers or fabrics through chemical bonding, chemical adhesion, adsorption deposition, and non-polar van der Waals forces; or by improving the thermal stability of fiber-forming polymers and modifying fibers to produce flame-retardant fibers, which are then woven into flame-retardant fabrics.

Research and Development of Flame-Retardant Fibers

There are two main approaches to improving the flame retardancy of textile fibers both domestically and internationally:

On the one hand, improving flame-retardant processes to enhance the flame-retardant properties of existing flammable fibers while maintaining their original performance; on the other hand, vigorously developing new types of flame-retardant fibers. To meet the diversified demands of the market, countries led by Japan have strengthened the development of durable, high-efficiency, and multifunctional flame-retardant fibers. These fibers, depending on their different uses and requirements, combine flame retardancy, heat resistance (high temperature), antibacterial and deodorizing properties, fragrance, corrosion resistance, antistatic properties, UV resistance, water resistance, and stain resistance.

The flame-retardant processing of traditional flammable fibers has evolved from using a single flame-retardant element to using two or more. For example, while acrylic fibers retain halogenated bromine as an additive due to cost considerations, they are still developing towards introducing phosphorus-containing and multi-component synergistic systems. From the perspective of fiber modification, development is moving towards dual (flame-retardant and conductive) and multiple modification methods.

There is a type of fire-retardant fabric made from aramid and ceramic fibers on the international market. Fire-resistant clothing made from this fabric is lightweight, breathable, and has three times the fire resistance of conventional fire-resistant clothing.

In recent years, Visil fiber, a self-flame-retardant fiber, has appeared on the European market. This high-silica viscose fiber produces less smoke, is non-toxic, and has an L0I of 26%-33%. It can be blended with flame-retardant aromatic polyamides and wool, and can be used in workwear, protective clothing, fireproof mats, filter media, and fillers. From the perspectives of flame retardancy, processability, and environmental degradability, it is an ideal flame-retardant fiber. PBO fiber, polymerized from diaminoisophthalic acid and special compounds, possesses excellent thermal stability, high strength, high elasticity, high charring resistance, and non-flammability.

Strengthening Research on Multifunctional Flame-Retardant Textiles

Currently, most flame-retardant fibers or fabrics only possess flame-retardant properties, failing to meet the specific requirements of certain sectors, such as flame retardancy with water and oil repellency, and flame retardancy with antistatic properties. Therefore, developing multifunctional flame-retardant products is imperative. This includes combining various production methods to waterproof and oil-repellent finishes on flame-retardant fiber fabrics; interweaving flame-retardant fiber yarns with conductive fibers to produce antistatic flame-retardant fibers; blending flame-retardant fibers with high-performance fibers to produce high-temperature resistant fabrics; and blending flame-retardant fibers with fibers such as cotton and viscose to improve the comfort of the final product and reduce costs.

Developing Environmentally Friendly, Smoke-Free, and Low-Corrosion Flame Retardants

In recent years, countries have accelerated the development of flame retardants, pursuing halogen-free, low-toxicity, smoke-free, low-pollution, and low-corrosion properties. High-efficiency multifunctional composite flame retardants and inorganic environmentally friendly flame retardants (ATH) are gaining attention. The traditional halobromine flame retardants are being replaced by new phosphorus-based and nitrogen-based flame retardants, and smoke-suppressing flame retardants are also under development.

Synergistic flame retardants have garnered attention due to their superior performance compared to single flame retardants and their ability to reduce costs and increase efficiency. Among them, phosphorus-nitrogen synergistic flame retardants, with their excellent synergistic effect, superior flame retardant performance, LOI exceeding 29%, and low smoke and toxic gas emissions, are particularly noteworthy.

Among non-halogenated flame retardants, inorganic flame retardants, while non-toxic or low-toxic, inexpensive, and possessing anti-dripping and smoke-suppressing properties, exhibit poor flame retardant effects and require large quantities. With the exception of a few, they are mostly used as auxiliary flame retardants. International research is underway to improve their effectiveness, reduce their usage, and lower costs.

Furthermore, in addition to developing new flame retardants for textiles, research is also drawing inspiration from flame retardants in other fields. For example, a Japanese company has launched a phosphorus- and ceramic-containing foamed heat-insulating flame-retardant coating that can be coated on fiber surfaces and foams up upon heating to retard flames.

Improving flame retardant regulations and conducting effective public awareness campaigns are crucial.

The improvement and perfection of laws and regulations play a vital role in promoting the development and application of flame-retardant textiles and in preventing fires caused by the flammability of textiles. To accurately evaluate the flame-retardant properties of textiles, standards should be developed based on the requirements of their intended use. Test methods should be based on actual fire conditions rather than small-scale laboratory experiments; this is the future direction for textile flame-retardant standards. Furthermore, public awareness campaigns on flame-retardant textiles should be conducted to ensure people understand them correctly and apply the established flame-retardant and fire-prevention regulations and standards to practical work.

Other Aspects

While traditional flame-retardant technologies impart certain flame-retardant properties to textiles, they often fail to achieve satisfactory hand feel and strength, among other mechanical properties. For example, polyester-cotton fabrics often experience reduced strength and poor hand feel after flame-retardant finishing. The overall performance of flame-retardant textiles is generally improved through blending techniques, composite flame retardants, and other methods to enhance flame-retardant processes. The use of single zirconium-titanium flame retardants in wool fabrics often affects the whiteness and luster of the wool, while composite flame retardants can overcome this deficiency. Protex, a novel fire-retardant carbon fiber, possesses good self-extinguishing and flame-retardant properties, but suffers from low strength and poor wearability. Blending it with other fibers can yield flame-retardant fabrics with improved wearability. Furthermore, the application of coating finishing and nonwoven technologies in flame-retardant processing is increasingly common.

Currently, the demand for flame-retardant protection is extremely urgent. Against this backdrop, researchers have a responsibility to widely and actively promote the crucial significance and urgency of "researching, producing, and applying flame-retardant textiles" to all sectors of society, thereby raising public awareness and attention to this work.

At the same time, it is crucial to keep pace with the times and promptly improve regulations and laws related to the use of flame-retardant textiles, providing a solid legal guarantee for their promotion and application. It is also essential to accelerate the improvement of testing methods and standards for the flammability performance of textiles, simultaneously conducting medium-scale tests and simulated fire tests on flame-retardant textiles to ensure that test results are closer to real-world conditions. Furthermore, it is vital to formulate scientific and reasonable product standards for flame-retardant textiles, especially tailored to different application scenarios, and to take effective measures to ensure their strict implementation.

It is important to recognize that a single flame-retardant testing method has limitations and cannot comprehensively and accurately reflect the flammability performance of materials. Therefore, multiple testing methods should be used in combination as much as possible. It is believed that with the continuous deepening of flame-retardant technology research, the ongoing improvement of flame-retardant testing methods, and the gradual establishment of a flame-retardant regulatory system, flame-retardant textiles will undoubtedly experience a surge in large-scale promotion and application.