Low-hydrated zinc borate flame retardant mechanism

Into organic flame retardants and inorganic flame retardants organic flame retardants include halogen, phosphorus and halogen - phosphorus; inorganic flame retardants are aluminum hydroxide, antimony trioxide, magnesium hydroxide , zinc borate, etc. of the inorganic flame retardants, antimony trioxide greater consumption,

But because it can not smoke suppression also has some toxicity, and therefore its use is subject to certain restrictions. Currently, there has been non-flame retardant antimony technology trends, can replace some or all of antimony trioxide flame retardant mainly zinc borate, tin, zinc, molybdenum compounds, etc. According to statistics, the occurrence of

Deaths caused by fire, 80% of which is generated by combustion of materials caused by smoke and toxic gases, therefore, in addition to having excellent flame retardant effect, low toxicity, low smoke also its essential properties borate zinc as an environmentally friendly inorganic flame retardant, with

Non-toxic, pollution-free, flame retardant and smoke suppression of excellent performance, especially low-hydrated zinc borate (2ZnO3B2O33.5H2O) after the advent gradually been widely applied. Zinc borate and other flame retardants (antimony trioxide, aluminum hydroxide etc.) complex to use, can significantly improve their smoke suppression, resistance

Combustion performance, with good market prospects.
Low-hydrated zinc borate flame retardant mechanism
1.1 Physical Properties lower hydrated zinc borate as a white crystalline powder, melting point 980 ℃, density of 2.71 × 103kg/m3, refractive index 1.58, a molecular weight of 434.66, toxicity LD50 (oral, rat)>, no toxic inhalation and contact the skin, the eyes do not produce irritation, no

Corrosive; insoluble in water, soluble in hydrochloric acid, sulfuric acid and dimethyl sulfoxide, soluble complexes generate ammonia; insoluble in ethanol, n-butanol, benzene and other organic solvents; heated to about 290 ℃ begins to lose crystal water, to 600 ℃, completely lost crystal water.
1.2 retardant plastic pyrolysis release mechanism H, and R radicals, H and the active oxygen in the air to generate a great HO, the rapid expansion of the flame can, both the formation of chain reaction H (resulting pyrolysis) + O2 → HO + O CO (pyrolysis proceeds) + HO → CO2 + H Thus, flame retardants should reach

To flame purpose, you need to: ① to reduce the temperature of ignition, preventing polymer pyrolysis of H and R radicals; ② able to cut off the air; ③ able to capture the activity of great HO, prevent flame expansion.
zinc borate flame retardant as a flame retardant to satisfy the above requirements, the flame retardant mechanism is:
1 heat and diluted zinc borate can be higher than 300 ℃ crystallization of water, can play a role in the cooling heat. Zinc borate, about 38% of zinc oxide, zinc hydroxide, zinc or form into the gas phase, the combustible gas is diluted so that the combustion rate decreases.
(2) forming the cover layer generally halogen flame retardant zinc borate compound and use, contact with fire and heat, the reaction equation is 2ZnO 3B2O3 3.5H2O +22 RX → 2ZnX2 +6 BX3 + 11R2O +3.5 H2O ZnX2 high boiling point, is a solid substance that can combustible material covered on the table

Isolated from the air side, inhibiting combustible gases, and also to prevent oxidation and the action of heat; contribute PVC decomposes to form an aliphatic hydrocarbon, ultimately beneficial for the dehydration reaction; acid can promote the generation of large amounts of carbon of carbon increases means combustible material escapes reduction

Have a good smoke suppression effect.
3 to prevent chain reaction when added to the zinc borate halogen polymer material, in the combustion gas generated after entering BX3 encounter with water vapor to generate HX, the flame generated radicals halogen atom, to prevent free radical inter chain reaction.