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Nylon flame retardant additive
2017-10-8 14:49:36
Nylon flame retardant additive
The advantage of nylon flame-retardant additive red phosphorus is the high effective phosphorus content, which produces more phosphoric acid than other phosphorous compounds when burning. When the same flame retardant grade is reached, the addition of red phosphorus is lower than other flame retardants, so that the nylon can maintain its mechanical properties better. The main drawback of red phosphorus as a flame retardant is its red color, flammability and the formation of highly toxic phosphine (phosphine) through water reaction. Microencapsulation of ordinary red phosphorus can avoid its disadvantages.
Nylon flame retardant additive ammonium polyphosphate (APP) by reducing the degradation of polyamide change in temperature, the composition of gas phase product involved in the process of thermal degradation of polyamide, at the same time in honeycomb carbonized layer is formed on the polymer matrix, partition two phase heat and mass transfer of the interface, have played an important role in the protection substrate.
Due to the flow tendency of carbon, the base material under the carbon layer is exposed, which increases the risk of combustion. Add some inorganic additives, such as Talc, MnO2, ZnCO3, CaCO3, Fe2O3, FeO, Al (OH) 3, etc., and flame retardant effects increase. Add one of the above additives (about 1. 5 % ~ 3. 0 %) to the 20 % of the application, and the LOI value rose from 25 to 35 ~ 47, to the V20 level.
Nitrogen flame retardant: nitrogen flame retardant is low toxicity, non-corrosive, stable to heat and uv, good in flame retardant efficiency and low price. The disadvantage is that it is difficult to process the flame retardant plastic, and the dispersion is poor in the substrate. The main flame retardants for nylon are MCA (melamine - tripolycyanate), melamine (melamine), and MPP (melamine phosphate).
On the flame retardant mechanism, on the one hand, is the sublimation heat absorption way of physical flame retardant, namely through the flame retardant "sublimation heat absorption" reduce the surface temperature of the polymer material and isolated from the air and reach the purpose of flame retardant, flame retardant with nylon on the other hand is a condensed phase catalytic direct expansion mechanism of carbide. MCA simultaneously promotes carbonation and foaming function during flame retarding. For different types of nylon, the flame retardant mechanism is slightly different, and the flame retardant effect is different.
Tris(2-chloroisopropyl)Phosphate(TCPP)
Tris(2-chloroisopropyl)Phosphate(Flame retardant TCPP) is a colorless or yellowish oily liquid. It is soluble in benzene, alcohol, carbon tetrachloride and other organic solvents, but insoluble in water and aliphatic hydrocarbons. Its relative density is 1.27-1.31, refractive index is 1.4916 ( 21.5 ), viscosity is 58mm2 / S, chlorine content is 32.8%, and phosphorus content is 9.5%. As the molecule contains phosphorus and chlorine element simultaneously, its flame retardant properties is significant, as well as the plasticization, damp-proof, antistatic effects and so on. Tris(2-chloropropyl) phosphate (TCPP) is an additive flame retardant.
The product is used for the soft / hard polyurethane foam, with thermal and hydrolytic stability good, especially suitable for ASTME84 (Level 11) foam, with low viscosity unsaturated polyester resin in low temperature application and phenolic plastics at. This product is also used to grab the foam sealant and sheet production. For polyvinyl chloride, polystyrene, phenolic resin, acrylic resin and rubber, coating, flame retardant, also used for soft and hard polyurethane foam, epoxy resin, polystyrene, cellulose acetate, ethyl cellulose tree and phenolic plastics, polyvinyl acetate and gun type foam sealant production. Particularly recommended for rigid polyurethane foam has excellent thermal and hydrolytic stability is particularly suitable for ASTM84 (II), compound for polyurethane foam and unsaturated resin and phenolic plastics.
Pieter Gijsman and Shahab Jahromi etc respectively studied the MCA and MPP in the mechanism of nylon 6 and nylon 66, found in the MCA and MPP nylon 66 leads to crosslinking, and encouraged the degradation in the nylon 6, nylon flame retardant additive flame retardant effect of nylon 66 is better than that of nylon MCA is made up of melamine and cyanuric acid synthesis of melamine in the water - cyanuric acid salt, is a kind of adduct by hydrogen bonding. It is an excellent flame retardant, with the advantages of halogen, low toxicity and low smoke. It is often used in the flame retardant of nylon polymer materials.
But traditional MCA high melting point (400 ℃ or more direct decomposition and sublimation), only in the form of solid particles and resin blend composite, so scattered unevenly, the dispersed phase size is big, affect the flame retardant effect; In addition, because MCA is mainly gas-phase flame retardant, the material condenses in the combustion process to a low carbon amount, and the carbon layer is loose, which can not form the dense protective layer, which also limits the improvement of the flame retardant efficiency.
Sichuan university using molecular composite technology in melamine cyanuric acid salt (MCA) molecules and its molecular structure is introduced into the complementary and itself has the flame retardancy of modifier W EX to reduce the melting point of MCA, and PA 6 eutectic compound, super fine dispersed homogeneously;
The flame retardant properties of flame retardant properties and excellent mechanical properties were prepared by using W EX in the combustion process of materials, improving the quality of carbon layer and enhancing the flame retardant effect of MCA flame retardant. The nylon used without halogen flame retardant MCA was developed by yueyang petrochemical research institute, with the addition of 18 % ~ 25 %, and the flame retardancy reached UL94V - 0.
Expansive flame retardant is an important kind of halogen free flame retardant system. The expansion of flame retardant is better than halogen flame retardants in the smoke when it burns, and the gas released is harmless. In addition, the expansion of flame retardants generate carbon layer can absorb the polymer melt, fire, to prevent the spread of its dripping fire. Study on expansion flame retardants mainly include the following: air supply source (melamine), acid (nitrogen phosphorus flame retardant), carbon source (PA) and auxiliary synergistic flame retardant, such as zinc borate, aluminum hydroxide, and dripping remover, etc.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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