What is flame retardant fabric? What makes flame retardant fabrics flame retardant?

Fire-proof fabric is to use technology to perform fire-proof treatment on the basis of colored cloth, or the fire-proof agent with fire-proof function is modified through polymer polymerization, blending, copolymerization, lamination spinning, and splicing extrusion modification and other technologies are added to the fiber to make the fiber fire-resistant. The post-finished product can effectively prevent the spread of flames and protect the original properties of the fabric. It can automatically extinguish or effectively slow down the spread of flames and carbonize the fabric to form an isolation layer. It also has the properties of not melting or dripping or delaying flames when exposed to fire. Characteristics, with better fire protection effect. (Fire-proof fabrics are not inflammable. Even if they are ignited by an open flame, they will automatically extinguish within 12 seconds after leaving the open flame)

1. Classification of fire-resistant fabrics

Fire-resistant fabrics can be divided into:

according to washability standards

1. Permanent fire-retardant fabric (woven with fire-retardant fiber, no matter how many times it is put into the water, the fire-retardant effect does not change)

2. Washing resistance (more than 50 times) fire-retardant fabric

3. Semi-washable fire-resistant fabric

4. Disposable fire-resistant fabrics (decorations, curtains, cushions, etc.)

2. The production process of fireproof cloth and the introduction method of additives can be divided into: fireproof treatment of fibers and fireproof finishing of fabrics

Fire retardant treatment of fiber:

1. Fire prevention mechanism refers to adding a certain fire retardant to some inherently flammable raw fibers (such as polyester, cotton, polyacrylonitrile fiber) to inhibit free radicals during the combustion process; or It changes the thermal decomposition process of the fiber and promotes dehydration and carbonization; in some cases, the fire retardant decomposes and releases non-flammable gas to cover the surface of the fiber and isolate the air.

2. Fire prevention treatment methods

1) Improve the thermal stability of fiber-forming polymers

2) Fireproof modification of raw silk

Fireproof finishing of fabrics:

1. Fire prevention mechanism

1) Covering layer theory: Fire retardant can form a glassy or stable foam covering layer at high temperatures, which has the functions of heat insulation, oxygen insulation, blocking combustible gas from escaping outward, and playing a fire prevention role.

2) Non-combustible gas theory: The fire retardant decomposes into non-combustible gas when heated, and the concentration of combustible gas decomposed from cellulose is diluted to below the lower combustion limit.

3) Endothermic theory: The fire retardant reacts endothermically at high temperatures, lowering the temperature to prevent the spread of combustion. In addition, the heat can be transferred out quickly after fabric finishing, so that the cellulose cannot reach the temperature of ignition and combustion.

4) Chemical reaction theory (catalytic dehydration theory): The fire retardant acts as a Lewis acid and reacts with the fiber at high temperatures, causing the fiber to catalytically dehydrate and carbonize, reducing the generation of flammable gases.

2. Post-fire prevention finishing methods

1) Padding and baking method: a widely used fireproof finishing process. The process flow is padding-prebaking-baking-post-processing. Padding fluid is generally composed of fire retardants, catalysts, resins, wetting agents and softeners, and is configured into an aqueous solution or emulsion for post-finishing.

2) Dip and bake method (absorption method): After immersing the tissue in the fire retardant liquid for a certain period of time, it is then dried and baked to allow the fire retardant liquid to be absorbed by the fiber polymer.

3) Organic solvent method: It uses a non-water-soluble fire retardant agent. Its advantage is low energy consumption during fire prevention finishing. However, in actual operation, attention should be paid to the toxicity and flammability of solvents.

4) Coating method: Mix the fire retardant into the resin, and the fire retardant is fixed on the fabric by the adhesion of the resin. According to different mechanical equipment, it is divided into blade coating method and pouring coating method.

3. Finishing process and commonly used additives for fire-retardant cloth

The current mainstream fire protection processes include the promethazine fumigation process and the CP finishing process. The Prubenzin process is suitable for formaldehyde that is not suitable for work clothes that are not worn close to the body. The advantage is that the loss of breaking strength of the fabric is small. The relative fastness of fabrics made from the same natural cotton fabric after finishing is much higher. Generally, Luben can basically meet the requirements of GB8965.1-2009 Class B standard, while CP can only meet the Class C standard of this standard, and it is basically difficult to achieve Class B standard. However, for fire-retardant clothing that is close to the skin, it is not recommended to use fabrics with proben finishing technology. Instead, it is recommended to use CP technology with low formaldehyde content or permanent fire-retardant fabrics such as acrylonitrile and Nomex. For customers with higher requirements for color and feel, it is also recommended to use fire-retardant fabrics made with CP technology or acrylonitrile and Nomex. At present, most customers still use fire-retardant work clothes made of fire-retardant fabrics made of polybenzene technology and finishing.

Process flow:

Proben: padding fireproof finishing fluid→
Pre-drying → Ammonia fumigation → Washing → Drying → Pre-shrinking → Finished product (requires hot air priming machine and ammonia fumigation machine)

CP: padding fireproof finishing fluid→
Pre-drying → baking → washing → drying → pre-shrinking → finished product (general dyeing factories can do this)

Commonly used additives:

According to the application method, they are divided into additive fire retardants and reactive fire retardants. According to the composition, additive fire retardants mainly include inorganic fire retardants, halogen fire retardants (organic chlorides and organic bromides), Phosphorus-based fire retardants (red phosphorus, phosphate esters, halogenated phosphates, etc.) and nitrogen-based fire retardants, etc.

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