Comparison of flame retardant properties of polyester-cotton blended fabrics flame retardants PN- and PN-
0. Foreword
Polyester-cotton blended chemical fiber fabrics are popular among consumers due to their excellent wearing properties and durability. However, because they are prone to burning, causing fire accidents and causing huge losses, fire-proof finishing is required. The research has received widespread attention [1]. So far, people have found that fireproofing polyester-cotton fabrics is far more difficult than fireproofing any of its components. The main reasons are: because cotton is a flammable fiber that does not melt or shrink. When polyester-cotton products burn, the cotton fibers are carbonized, which acts as a candle-wick-like support for the polyester, thereby preventing the polyester from burning. The molten droplets are separated from the fire source; secondly, the mutual thermal induction of polyester and cotton polymers or their cracking products accelerates the overflow of the cracking products, so the polyester-cotton fabric ignites faster than pure polyester and pure cotton. Third, during the combustion process, the fire retardant can migrate between the polyester and cotton components. Therefore, it also brings difficulties to the fire protection of polyester-cotton fabrics. At the same time, when the polyester-cotton blended chemical fiber fabric is heated, the heated and melted polyester component will cover the surface of the polyester fiber, and the polyester fiber and the char generated by its cracking will form a skeleton, preventing the fabric from shrinking, causing the molten polyester to become part of the fire zone. This kind of fuel makes the fabric burn more violently [2].
Therefore, to reduce the flammability of polyester-cotton blended chemical fiber fabrics, the following points must be achieved: (1) Each component of the blended chemical fiber fabrics must be fireproofed. (2) When finishing the fireproofing of blended chemical fiber fabrics, use appropriate fireproofing agents, which can complement each other or not interfere with each other. (3) Eliminate the bone price effect and the interference of the two components.
Phosphorus-nitrogen fire retardant is one of the most effective fire retardants on pure cotton fabrics. At the same time, due to the synergistic effect between phosphorus and nitrogen, it is also widely used in polyester-cotton blended chemical fiber fabrics. Progress. This article uses tetrahydroxymethylphosphorus chloride (THPC) and amide compounds to react with ammonia to form a water-soluble preshrunk as fire retardants PN-1 and PN-2. Fire retardant agents PN-1 and PN-2 utilize the phosphorus-nitrogen fire retardant system, which has a significant synergistic effect on the solid phase fire retardant of cellulose fibers. Because the addition of nitrogen-containing compounds can reduce the amount of phosphorus fire retardant and improve the fire prevention effect. At the same time, nitrogen and phosphorus will first form a phosphorus amide structure, and then generate a P-N bond, which can enhance the phosphorylation reaction ability with the primary hydroxyl group of the fiber and inhibit the production of levoglucose. When the fabric ignites, the phosphorus in the fire-proof polymer reacts with oxygen in the air to form phosphorus pentoxide (P2O5). Phosphorus pentoxide is a strong dehydrating agent that can remove fibers from fibers. Taking out water molecules, when phosphorus pentoxide meets water, it generates polyphosphoric acid. The polyphosphoric acid will continue to remove the water in the fiber. In fact, it reduces the cellulose into non-combustible charcoal. At the same time, the polyphosphoric acid is also easily packaged. Covers the outside of the fiber to inhibit the reaction with oxygen and avoid the generation of flammable gas carbon monoxide. When the cotton fiber is carbonized, it becomes the skeleton of the synthetic fiber, which is equivalent to the carbon fiber. The synthetic fiber is distributed in the middle of the carbon fiber. At this time, most of the synthetic fiber is also carbonized and cannot burn. As a result, the burning of the fabric is blocked. {3}.
This article mainly conducts a comparative study on the fire retardant properties and finishing conditions of polyester-cotton blended chemical fiber fabrics with fire retardants PN-1 and PN-2.
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