Silicone flame retardant system
New flame retardant modification methods for silicon series include silicone-based flame retardants and inorganic silicon-based flame retardants. Silicone-based flame retardants are mainly siloxane compounds. For example, flame retardant polymers using silicone-based flame retardants Acrylonitrile fiber has the advantages of no toxic gas generated during combustion and no melting dripping. At present, inorganic silicon-based flame retardants mainly adopt the form of polyamide / inorganic clay nanocomposites. Foreign countries have also studied the addition of nano-layer silicate materials in the polyester polymerization process or spinning melt to modify the physical and mechanical properties and combustion properties of polyester materials. The Chinese Academy of Sciences Institute of Chemistry has also carried out research work in this area, and has made certain achievements.
The ultra-fineness of inorganic flame retardants has become a hot spot in the development of flame retardant technology today. The method of dispersing the solid flame retardant into particles with a size of l-100nm using physical or chemical methods is called nano flame retardant technology. The physical methods include evaporation condensation method and mechanical crushing method; the chemical methods include gas phase reaction method and liquid phase method. For example, the antimony trioxide passes through the plasma arc of the tail gas reaction evaporation area to evaporate, and then enters the condensing chamber for quenching, which can obtain 0.275nm antimony trioxide particles. The ultra-fine flame retardant treatment technology can not only improve the flame retardant efficiency and reduce the amount of flame retardant, but also have a great impact on improving the smoke resistance, weather resistance and coloring of the flame retardant. In recent years, colloidal antimony trioxide developed abroad has the characteristics of small particle size (less than 100nm), easy dispersion, low color strength, etc., and has achieved good results in the practical application of flame retardant fibers.
Microcapsule technology is to wrap the flame retardant particles, such as surface treatment of aluminum hydroxide and magnesium hydroxide with silane and titanate; or to absorb the flame retardant in the voids of the inorganic carrier to form honeycomb microcapsule Flame retardants, which can improve the compatibility of flame retardants and polymers. Silane molecules and titanate molecules form a "molecular film layer" on the surface of aluminum hydroxide and magnesium hydroxide particles, and a "bridge bond" is formed between the flame retardant and the polymer; using silicate and silicone resin, The organic flame retardant that is easily decomposed by heat can be well protected, thereby effectively improving the thermal stability of the flame retardant. At home and abroad, a lot of research has been done on the microencapsulation of flame retardants such as red phosphorus and ammonium polyphosphate. The microencapsulated red phosphorus and polyamide blend spinning can also obtain flame retardant polyamide fibers with self-extinguishing properties. Encapsulated ammonium polyphosphate can also be used for flame retardancy of polypropylene fibers.
During the flame retardant treatment of the material, it was found that the simultaneous use of certain flame retardants will achieve a good synergistic effect and obtain a more ideal flame retardant effect. For example, phosphorus plus halogen, antimony plus halogen, phosphorus plus nitrogen, phosphorus plus crystalline water compound, etc. This compounding method is called compounding technology. The compound application of halogen-phosphorus-silicon compound has better flame retardant effect, and halogen, phosphorus and silicon have flame retardant synergistic effect. At high temperatures, halogen and phosphorus promote the formation of carbon, silicon increases the thermal stability of these carbon layers, and when siloxane is used instead of silane, the flame retardant synergy between the two phosphorus elements is further strengthened.
Synthetic fiber flame retardant development direction
The development of synthetic fiber flame retardant technology should be developed in the direction of multi-functionalization, while improving the flame retardant efficiency, the fiber has other properties at the same time, such as flame retardant normal temperature easy-dyed polyester fiber, etc .; improve the flame retardant in the fiber Compatibility and mixing uniformity; the application of the new flame retardant system in the flame retardant modification of fibers, etc., so that the market prospect of flame retardant fiber industrialization will be very broad.
The functional compounding of flame retardants is becoming a new development trend, and countries around the world are now developing dual-functional and multi-functional flame retardants. It is hoped that by adding a composite material, it can play the dual functions and versatility of flame retardant antistatic or flame retardant easy dyeing, flame retardant and antibacterial, for example, the use of antistatic flame retardant and polyester chips blended spinning The method prepared antistatic flame retardant polyester fiber. At present, countries such as Europe, America and Japan have produced inorganic composite flame retardants such as aluminum hydroxide, silica, zinc borate and other inorganic substances with flame retardant and smoke suppression functions and antimony trioxide. Treating the flame-retardant fiber with fluoride not only helps the flame-retardant durability of the fiber, but also can effectively improve the fiber's waterproof performance.