Wool is a natural protein fiber physical, chemical structures are more complex, its soft texture, color fastness, good flexibility and warmth; natural, soft gloss, a wide range of applications in the field of architecture, taking home textile, which on subsequently finishing put forward higher requirements.
Wool limiting oxygen index of about 25 or so, a flash point of 570 to 600 ℃, the maximum combustion temperature of 680 ° C, as a natural flame retardant fiber. And its combustion does not melt or drip, the foam produced ashes has good insulating properties. These properties are closely related to its chemical structure, the wool high moisture regain of 15% (relative humidity 60%), nitrogen containing 15% to 16%; sulfur content of 3% to 4%; further contains 6% to 7% of hydrogen. The high nitrogen content of the decision itself has good flame retardant properties, if more of its flame-retardant finishing, can develop more high-performance products, such as high-temperature protective clothing, decorative materials on the aircraft and blankets, fuel vehicles canopy cover.
Combustion mode and flame retardant way
The wool fabric burning need to have three elements: fuel, heat and oxygen.
To achieve the flame retardant effect, and the need to break the above mode, as follows:
(1) the removal of the heat source. So that not enough heat to maintain the combustion. Most of the organic phosphorus flame retardant, and Al (OH) 3 of this mechanism, the combustion catalytic dehydration heat away so that the fiber is difficult to continue the combustion.
(2) improve the decomposition temperature. Production of fire fighter clothing modified by strand or fiber blends under this mechanism.
③ reduce contact with O2 gas dilute theory. A halogen-based flame retardant is this mechanism, the hydrogen halide gas generated during the combustion, oxygen diluted around fibers.
④ to reduce the generation of the combustible gas, increasing the formation of carbonized material. The the most phosphorus - nitrogen-based flame retardants and metal complex fireproof of this mechanism, carbon residue generated during the combustion, a heat-insulating layer is formed on the fiber surface, preventing the diffusion of heat to the fibers, so as to achieve the purpose of flame-retardant.