What is flame retardant fabric? What makes flame retardant fabrics flame retardant?
Flame-retardant fabrics are flame-retardant treatments based on dyed fabrics, or flame retardants with flame-retardant functions are polymerized, blended, copolymerized, and composite spun. , joint extrusion modification and other technologies are added to the fiber to make the fiber flame retardant. The finished product can not only effectively prevent the spread of flames, but also protect the original properties of the fabric. It can automatically extinguish or effectively slow down the spread of flames, carbonize the fabric to form an isolation layer, and at the same time has the characteristics of not melting or dripping or delaying flames when exposed to fire. , has good flame retardant effect. (Flame-retardant 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 flame retardant fabrics
Flame-retardant fabrics can be divided into:
1.Permanently flame-retardant fabric (woven with flame-retardant fibers, the flame-retardant effect does not change no matter how many times it is put into the water)
2.Washing resistance (more than 50 times) flame retardant fabric
3.Semi-washable flame retardant fabric
4.Disposable flame retardant fabrics (decorations, curtains, cushions, etc.)
2The production process of flame-retardant fabrics and the introduction of additives can be divided into: flame-retardant treatment of fibers and flame-retardant finishing of fabrics
Fiber flame retardant treatment:
1. Flame retardant mechanism refers to adding a certain flame retardant to some inherently flammable raw fibers (such as polyester, cotton, acrylic) to make them Inhibit free radicals during the combustion process; or change the thermal decomposition process of the fiber to promote dehydration and carbonization; some decompose the flame retardant and release non-flammable gas to cover the surface of the fiber to isolate the air.
2. Flame retardant treatment method
1) Improve the thermal stability of fiber-forming polymers
2) Flame retardant modification of raw silk
Flame retardant finishing of fabrics:
1, flame retardant mechanism
1) Covering layer theory: Flame retardants can form a glassy or stable foam covering layer at high temperatures, which has the functions of heat insulation, oxygen insulation, and flammable gas prevention Escapes outward and plays a flame retardant role.
2) Non-flammable gas theory: The flame retardant decomposes into non-flammable gas when heated, and dilutes the concentration of flammable gas released from cellulose to below the lower combustion limit.
3) Endothermic theory: Flame retardants undergo endothermic reactions 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 flame retardant reacts with the fiber as a Lewis acid at high temperature, causing the fiber to catalytically dehydrate and carbonize, reducing the Generation of flammable gases.
2. Flame retardant finishing method
1) Padding and baking method: a widely used flame retardant finishing process. The process flow is padding-prebaking-baking-post-processing. The padding fluid is generally composed of flame retardants, catalysts, resins, wetting agents and softeners, and is configured into an aqueous solution or emulsion for processing.reason.
2) Dip and bake method (exhaustion method): The tissue is immersed in the flame retardant liquid for a certain period of time, and then dried and baked to make it flame retardant. The liquid is absorbed by the fiber aggregate.
3) Organic solvent method: It uses non-water-soluble flame retardant. Its advantage is low energy consumption during flame retardant finishing. However, in actual operation, attention should be paid to the toxicity and flammability of solvents.
4) Coating method: Mix the flame retardant into the resin, and the flame 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 flame retardant fabrics
The current mainstream flame retardant processes include promethazine fumigation process and CP finishing process. The Prubenzin process allows appropriate formaldehyde for clothing that is not worn next 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 gray fabric after finishing is much higher. Basically, Prubenzin is It can meet the requirements of GB8965.1-2009 Level B standard, while CP can only meet the Level C standard of this standard, and it is basically difficult to achieve Level B standard. However, for flame-retardant clothing that is close to the skin, it is not recommended to use fabrics with proben-finished technology. Instead, it is recommended to use CP technology with low formaldehyde content or permanent flame-retardant fabrics such as acrylonitrile and aramid. For customers with higher requirements on color and feel, it is also recommended to use flame-retardant fabrics made of CP process or acrylonitrile and aramid. At present, most customers still use flame-retardant fabrics made of flame-retardant fabrics finished with polybenzene process on their jackets. Work clothes.
Process flow:
Pluben: padding flame retardant finishing fluid→
Pre-drying → Ammonia fumigation → Washing → Drying → Pre-shrinking → Finished product (requires hot air primer and ammonia fumigation machine)
CP: padding flame retardant finishing fluid→
Pre-drying → baking → washing → drying → pre-shrinking → finished product (general dyeing factories can do it)
Commonly used additives:
According to the application method, it is divided into additive flame retardants and reactive flame retardants. According to the composition, additive flame retardants mainly include inorganic flame retardants, Halogen flame retardants (organic chlorides and organic bromides), phosphorus flame retardants (red phosphorus, phosphate esters, halogenated phosphates, etc.) and nitrogen flame retardants, etc.
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