The so-called "flame retardant", not the flame-retarded textile will not burn when it comes into contact with the fire source, but the fabric can reduce its flammability in the flame, can slow down the spread speed, and does not form a large burning, leaving After the flame, it can self-extinguish quickly, no longer burning or smoldering.
The mechanism of flame retardant action is physical and chemical. According to the existing research results, it can be summarized as follows :
(1) Endothermic effect. A flame retardant having a high heat capacity undergoes an endothermic decomposition reaction such as phase transformation, dehydration or dehydrohalogenation at a high temperature, lowers the temperature of the fiber material and the flame zone, slows down the rate of the pyrolysis reaction, and suppresses the flammable gas. generate.
(2) Cover protection. After the flame retardant is heated, it melts on the surface of the fiber material to form a glassy coating layer, which becomes a barrier between the condensed phase and the flame. In this way, oxygen can be isolated, the diffusion of flammable gases can be prevented, heat conduction and heat radiation can be blocked, and heat fed back to the fiber material can be reduced, thereby suppressing thermal cracking and combustion reaction.
(3) Gas dilution. The endothermic decomposition of the flame retardant releases non-combustible gases such as nitrogen, carbon dioxide, sulfur dioxide and ammonia, so that the flammable gas concentration at the cracking of the fiber material is diluted below the combustion limit. Or insufficient oxygen in some areas of the center of the flame to prevent combustion from continuing. In addition, this non-combustible gas also has a heat-dissipating effect. Their order of flame retardancy is : NZ>coZ>502>NH3 .
( 4 ) The condensed phase is flame retardant. Through the action of the flame retardant, in the condensed phase reaction zone, the thermal cracking reaction history of the fiber macromolecular chain is changed to promote dehydration, condensation, cyclization, cross-linking, etc., until carbonization, to increase the carbonization residue and reduce the flammable gas. The production of the flame retardant in the condensed phase plays a flame retardant role. The effect of the flame-retardant effect of the condensed phase is closely related to the matching of the flame retardant with the chemical structure of the fiber.
(5) Gas phase flame retardant. Through the thermal decomposition products of the flame retardant, a large amount of high-energy light-based radicals and hydrogen radicals are captured in the flame region, and their concentrations are lowered , thereby suppressing or interrupting the chain reaction of combustion, and exhibiting a flame retarding effect in the gas phase. Vapor phase flame retardant is not sensitive to the chemical structure of the fiber material.
(6) The surface effect of the particles. If a certain amount of inert particles are mixed in the combustible gas, it can not only absorb the heat of combustion, but also reduce the temperature of the flame. Moreover, like the wall of the container, on the surface of the particle, a large amount of high-energy hydrogen in the gas phase combustion reaction is free. Base, converted to low energy peroxy radicals. Thereby suppressing gas phase combustion.
The flame retardant effect is very complicated due to the molecular structure of the fiber and the type of the flame retardant, and is not limited to the above. In a particular flame retardant system, one of the above flame retardants may be involved, but in practice often includes multiple flame retardants.
Industrial sectional doors are the most durable and longest lasting doors to ensure circulation at the areas of the factory entrance and exit of goods, loading and unloading areas.
The body of sectional door is forming by 40 mm sandwich panels. These panels provides sound and heat insulation due to the intense doped polyurethane insulation was injected between galvanized steel sheet. (50 kg/m3).
Industrial sectional door systems provide space-saving with opening parallel to the ceiling.Any opening can be used clearly . and produces in accordance with the transition range and the height in the factory buildings or warehouses.
Doors is working sliding by be the most appropriate the gap between the top level of the gate with a ceiling height within the side rasils. The door can be mounted in different ways according to the gap distance (standard, low, highlift and vertical track systems).
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