The importance of flame retardant protection in the new era

National Defense Fire Retardant Textiles

President of the Military and Textile Branch of the China Industrial Textiles Association, Chen Xuwei

The procurement and production of military textiles have evolved significantly over the years. As times change and market demands shift, both supply and demand sides are now more open to communication, which has led to improved cost performance for military textiles. Flame-retardant fibers play a crucial role in this field. These include aramid 1313, aramid 1414, heterocyclic aramid, arylsulfone, carbon fiber, and vinylon. These fibers are primarily used as intermediate materials in protective clothing, anti-inflation suits, and other specialized applications.

The requirements for these textiles emphasize light weight, resistance to aging, high strength, ease of dyeing, flame retardancy, waterproofness, and breathability. Notably, the Shenzhou 7 space suit's outer layer has made significant breakthroughs in heat resistance and radiation protection, featuring tear-resistant, wear-resistant, heat-resistant, and micro-meteorite-resistant properties, along with chemical and ionizing radiation resistance.

Flame-retardant fibers are also widely used in parachute components such as canopies, ropes, straps, and covers. While some parts like buttons and pull tabs may be made of metal, the main structure is composed of flame-retardant composite fibers. Modern parachutes require advanced textile materials that are lightweight, strong, resistant to aging, flame-retardant, non-flammable, anti-static, and capable of maintaining stable tensile and tear strength. They also need to adapt to varying air permeability and allow controlled one-way extension based on specific use cases.

Beyond special clothing, flame-retardant fibers are applied in netting, gun covers, aircraft blankets, tents, and camouflage nets. For instance, the Chameleon camouflage material developed by the Second Artillery Armament Research Institute uses flame-retardant composite fibers as its primary component.

Textile Flame Retardant Finishing Technology and Product Development

Ph.D. Supervisor at Donghua University, Cai Sheng

Fabric combustion typically involves three stages: thermal decomposition, ignition, and sustained burning. Flame retardants target different aspects of these stages, forming various mechanisms such as endothermic reactions, free radical inhibition, melting theory, non-flammable gas generation, and condensed phase flame retardation.

Flame retardants can be classified into inorganic and organic types. Inorganic ones serve both as flame retardants and fillers, while organic ones fall into phosphorus- or halogen-based categories. Halogen-based options, including chlorine and bromine compounds, are commonly used but face environmental concerns.

Flame-retardant fibers are produced through methods like coating, blending, copolymerization, graft modification, and sheath-core spinning. Fabric finishing techniques include padding, baking, impregnation, drying, coating, spraying, and solvent treatment.

With the growth of the automotive and rail industries, the demand for high-quality flame-retardant interior fabrics has increased. A single train requires about 1,000 meters of seat fabric, while each car needs around 20 meters of textiles, with over 80 design variations.

In 2007, high-end automotive interior textiles needed flame resistance, moisture absorption, breathability, color fastness, UV resistance, anti-static, and anti-pilling properties—exceeding standard textile requirements. China’s domestic development was limited, and high-end products were dominated by Japan and Europe. Challenges included excessive smoke, poor heat resistance, stickiness at high temperatures, high smoke density, toxicity, and droplet formation.

To address these issues, we developed P-T expansive flame retardants that are formaldehyde- and halogen-free, with good thermal and hydrolytic stability, high melting points, and low moisture absorption. These were successfully used in high-speed train seat fabrics, meeting U.S., French, British, and German standards. They have been applied in projects by companies like France’s SNCF and Siemens.

Why Use Protective Clothing

Geoff, a Personal Protection Expert from a European Fiber Company

Proper selection and use of flame-retardant protective clothing can prevent severe fire-related injuries and save lives. Compared to the high costs of post-burn medical treatment, the cost of protective clothing is relatively low and highly effective. Wearing inappropriate clothing can lead to more severe burns than exposed skin would suffer in a fire.

More countries are enacting laws requiring workers in hazardous environments to wear appropriate personal protective equipment (PPE). Companies like Malaysia Petroleum, Shell, and Alcoa have implemented PPE policies for both full-time and contract workers. In China, similar regulations are being adopted across many industrial sectors.

Calculations show that every 1% of skin burn requires an average hospital stay of 1.5 days, with an average of 19 days and costs exceeding $18,000 per day. Hospitalization costs range from $200,000 to $700,000, often surpassing $1 million in severe cases.

Flame-retardant fabrics self-extinguish when the flame source is removed. This is achieved through flame-retardant finishing, which involves applying chemicals to make the fabric less flammable. However, some treated fabrics may contain harmful substances like formaldehyde, and their flame-retardant properties may diminish with frequent washing. In contrast, inherently flame-retardant fabrics, such as aramid or cellulose-based fibers, maintain their properties even after repeated washes.

Flame-retardant testing includes vertical burning tests, 12-second flame exposure, less than 6 inches of charred area, and under 2 seconds of afterflame. Correct use of protective clothing can significantly reduce injury risks. Future industries likely to adopt protective clothing include power grids, natural gas companies, steel plants, and firefighting services.

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