What is Flame Retardant Fabric?

Flame retardant fabric refers to a type of fabric made from flame retardant fibers or treated with flame retardant chemicals to reduce its flammability to varying degrees. It significantly delays the burning rate during combustion and can quickly self-extinguish after leaving the source of the fire, releasing minimal toxic smoke. Flame retardant fabrics can also have additional functions, such as anti-static, oil-resistant, water-resistant, and UV-resistant. When a fabric has two or more of these functions, it is called a multi-functional flame retardant fabric.

Advantages of BEGOODTEX Flame Retardant Fabric Include:

1. Good safety performance – the fiber does not melt and emits low smoke when exposed to fire.

2. Inherent (permanent) flame retardant effect – washing and friction do not affect the flame retardant performance.

3.Environmental protection is ensured by using natural fibers as carriers, which can naturally degrade, meeting environmental requirements.

4. Excellent flame retardant and fire-resistant properties – demonstrating good performance in preventing flame spread, smoke release, melting resistance, and durability.

5.Good thermal insulation and anti-static properties provide comprehensive thermal protection.

6. Natural Fiber Characteristics – The fabric possesses the absorbent and breathable properties of natural fibers, along with a soft, comfortable, and brightly colored texture.

Classification of Flame Retardant Fabrics According to Material Processing Methods:

1. Fiber Flame Retardant (Inherent Flame Retardant Fabric)

A blend fiber is made by copolymerizing flame retardant monomers with high polymers or adding flame retardant agents to polymers. The blend fiber is then woven into flame retardant fabric. Flame retardant fibers are incorporated with flame retardant during the drawing process, fused with fibers, and retain their flame retardant effect no matter how many times they are washed. Synthetic fibers can be spun and woven using flame retardant fibers, or flame retardant finishing agents can be applied to fabrics to achieve flame retardancy. Natural fiber fabrics can only achieve flame retardancy through flame retardant finishing.

2. Fire Retardant Treated (FRT)

The process includes coating with fire retardant, immersion in fire retardant, and spraying with fire retardant. For example, sand releases generally use a coating of fire retardant to prevent the fabric surface from being affected by fire retardant, which could cause changes in color and texture. Curtains are mostly treated with immersion fire retardant, which requires good draping. Window screens are treated with spray fire retardant, which minimally alters the original characteristics of the fabric.

Classification by the Wash Resistance of Flame Retardant Effect.

1. Temporary flame retardant textiles are flame retardant textiles that lose their flame retardant properties after washing. They are mainly used for textiles that do not need to be washed during use, such as upholstery and electric blanket fabrics.

2. Semi-durable flame retardant textiles – These textiles have flame retardant effects that can withstand 1-15 mild washes. They are commonly used for items like curtains, stage curtains, etc.

3. Durable flame retardant textiles – the flame retardant effects can withstand 50-200 soap washes. Flame retardant textiles have a wide range of applications, including clothing and bedding.

4. Inherent (permanent) flame retardant textiles are made from flame retardant fibers and have inherent (permanent) flame retardant effects. Flame retardant fibers are incorporated during the drawing process, fused with fibers, and retain their flame retardant effect even after washing.

In general, some cotton decorative fabrics and products that are rarely washed can be temporarily flame-retardant treated; indoor decorative fabrics such as curtains, mattresses, and electric blankets require semi-durable flame-retardant treatment; and clothing, bed sheets, pillowcases, work clothes, etc.require durable flame-retardant treatment. Of course, as the durability of the treatment effect improves, the cost also increases.

Classified by Burning Characteristics of Fibers.

Flame retardant fabrics are classified according to fiber burning characteristics. Due to the diverse chemical structures of various fiber materials, their combustion performance also varies. According to the ease of ignition, burning speed, self-extinguishing properties, and other burning characteristics of fibers when they are burned, fibers can be qualitatively classified into flame retardant fibers and non-flame retardant fibers. Flame retardant fibers include non-flammable fibers and difficult-to-burn fibers, while non-flame retardant fibers include flammable fibers and easily flammable fibers.

Classification by Composition Content

According to the composition of materials, flame retardant fabrics are classified into different categories, such as aromatic polyester flame retardant fabrics, eco-friendly flame retardant fabrics, all-cotton flame retardant fabrics, CVC flame retardant fabrics, and nitrile cotton flame retardant fabrics.

Flame Retardant Fiber Manufacturing Methods.

Flame Retardant Polyester

Polyester is a combustible thermoplastic fiber that softens, melts, shrinks, and forms droplets that move away from the heat source when exposed to fire. Before reaching the ignition point of the fiber, most of the heat is consumed in the melting process. It can be considered that the lower the softening point and melting point of the fiber, and the greater the difference between the melting point and the ignition point, the more difficult it is to ignite. Due to the low combustion heat of polyester, it has a slow combustion speed. The amount of smoke produced by polyester combustion is moderate, and the toxicity of the smoke is low.

“Co-polymerized Flame Retardant Modification” refers to the incorporation of phosphorus-based or bromine-based flame retardant monomers with reactive groups during the synthesis of polyester. These monomers can co-polymerize with terephthalic acid and ethylene glycol. The flame retardant fibers prepared with phosphorus-based monomers often have poor hydrolysis resistance, and the viscosity of the polymer decreases during spinning and dyeing processes. Flame retardant fibers prepared with bromine-based monomers have poor heat and light resistance. Commonly used flame retardant co-monomers include phosphate esters, phenylphosphonic acid derivatives, brominated aromatic diacids, tetrabromobisphenol A and its alkyl derivatives, etc.

The “Blend Flame Retardant Modification” process has lower requirements compared to co-polymerization, making it a more commonly used method for flame retardant modification of polyester fibers. The added flame retardant should not decompose or sublime at the spinning temperature and should have good compatibility with the polyester melt, without any adverse effects on the melt viscosity and fluidity. The particle size of the flame retardant should be below 1 µm, preferably less than 0.5 µm. Large particle size of the flame retardant will affect the strength of the fiber and cause breakage during spinning and stretching processes.

Cotton Flame Retardant

Cotton flame retardant fabric is achieved by applying flame retardant treatment to cotton fabric. The flame retardant treatment process mainly includes PROBAN, PYROAVTEX, etc. Cotton flame retardant fabric exhibits good flame retardant and fireproof performance without compromising the original comfort of the fabric. It retains the characteristics of cotton fiber, such as breathability, comfort and softness to the touch.

Temporary or semi-durable flame retardant finishing of cotton fabrics is mainly achieved by impregnating substances such as ammonium dihydrogen phosphate, diammonium hydrogen phosphate, urea, borax, boric acid and ammonium polyphosphate onto the fabric through dip-drying or impregnation, followed by baking. Some flame retardants may exhibit moisture absorption or crystallization phenomena during fabric storage and use, thus requiring careful selection. The typical durable flame retardant finishing process is Proban finishing. Proban finishing is a patent of the British Albright and Wilson Company, which holds a world-leading position in phosphorus-based fabric flame retardants. The main flame retardant finishing agent products are Proban and Amgard.

BEGOODTEX Proban Amgard

Proban finishing is a durable flame retardant finishing process for cotton and other cellulose fabrics and cellulose-based blended fabrics, which is based on tetrakis(hydroxymethyl)phosphonium chloride (THPC) and urea formaldehyde resin. The finishing process is: impregnation

The Standard of BEGOODTEX Flame Retardant Fabrics.

Flame Retardant Standards for Textiles.

There are several indicators for evaluating the flame retardancy of materials in the testing of flame retardant textiles, including the following:

• Ease of ignition

• Flame surface spread rate

• Heat release

• Visibility of smoke

• Toxicity of combustion products

• Corrosivity of combustion products

The first two indicators are collectively referred to as “reaction to fire” and are the primary factors for evaluating flammability.

1. Basic Test Methods

The so-called basic test methods refer to the techniques used to measure the combustion breadth (charred area and damage length), sustained burning time, and afterglow time of materials. A specific specimen size is ignited with a designated ignition source for 12 seconds in a specified combustion chamber. After removing the ignition source, the sustained burning time and afterglow time of the specimen are measured. After the afterglow stops, the damage length (character length) is measured according to the prescribed method. Based on the relative position of the specimen and the flame, the methods can be classified as vertical, inclined, and horizontal methods. Generally speaking, the vertical method is more stringent than other methods and is suitable for decorative fabrics, tents, aircraft interior decoration materials, etc. The inclined method is suitable for fabrics used in aircraft interior decoration, while the horizontal method is more appropriate for regular fabrics used in clothing. The Chinese standard GB/T 5455-2014 is applicable for testing various fabrics.
2. Limiting Oxygen Index Test

The test is conducted using an oxygen index meter. A specific size of specimen is clamped in the combustion tube of the sample holder, and the ratio of oxygen to nitrogen is adjusted. The specimen is ignited using a specific igniter to burn for a set period until it self-extinguishes or the damage length reaches a specific value. The oxygen and nitrogen flow rates at that time can be used to calculate the limiting oxygen index value of the specimen. The Chinese standard GB/T 5454-1997 stipulates that the limiting oxygen index value of a specimen is determined by the percentage of oxygen required for the specimen to self-extinguish after burning for precisely 2 minutes or for the damage length to reach exactly 40mm.
3. Surface Burning Test

For floor coverings, the heat radiation source method or the tablet method can be used. The heat radiation source method utilizes a combustible gas-powered heat radiation plate tilted at 30°, facing the horizontally positioned floor sample.
4. Other Test Methods

In order to make the experimental conditions closer to the actual situation, some countries have established small laboratories, such as the Insurance Industry Laboratories (LIL) in the United States. However, these small laboratories are highly arbitrary and limited, relying mainly on experience and deviating greatly from actual fire situations. Europe believes that in certain special situations, standard large-scale tests, such as the corner wall test, should be used directly. The corner wall test is closer to actual fire situations.