Glass fiber reinforced polyester, also known as polyester FRP, one of its main components is an unsaturated polyester resin and glass fiber composition. Because of its easy processing, light weight, high strength, corrosion resistance, good electrothermal performance, low cost, it is widely used in industry, construction, transportation, mining and other fields. However, the polyester resin made of FRP is flammable, 20% is unsaturated resin combustion oxygen index (LOI) , so the actual use of the need to enhance the flame retardant properties of FRP.
In the past, halogen -containing organic flame retardants, halogen -containing organic flame retardants+SB2O3, etc. are the most used methods in the past, but a large amount of black smoke and toxic gases will be released when burning, and they have gradually been restricted. In recent years, people’s demand for polyester glass reinforcement with the performance of halogen -free, smoke suppression, flame retardant and other properties has become increasingly urgent due to the consideration of fire prevention and life and property safety. Therefore, a new inorganic flame retardant -magnesium hydroxide has been increasingly widely used.
In the past, in the flame retardant glass fiber fiber reinforcement, aluminum hydroxide (ATH) was the most useless flame retardant, and at the same time, it has a variety of advantages such as adding, non -toxic, flame retardant, and smoke suppression. The lower heating temperature is stable than 205 ° C. Once it exceeds 220 ° C, it will decompose. Therefore, when using this type of polyester glass reinforcement, pay attention to the temperature limit of 205 ° C, and the range of use is subject to a certain limit.
Compared with aluminum hydroxide, magnesium hydroxide flame retardant is extremely similar to the cigarette elimination mechanism and aluminum hydroxide, but magnesium hydroxide has outstanding advantages that various aluminum hydroxide does not have.
First of all, the decomposition temperature of magnesium hydroxide is high. It is heated to 340 ° C before it starts to decompose into water and magnesium oxide. It not only has good flame retardant effect, but also meets the market’s demand for flame -resistant glass reinforced reinforcement of high temperature resistance.
Secondly, the activity MGO generated by magnesium hydroxide is easily absorbed by free radicals and carbon, which can delay the time of ignition of the material. Its catalytic oxidation function can reduce the speed of smoking and renewal.
At the same time, the smoke suppression capacity of magnesium hydroxide is double the aluminum hydroxide, which can better avoid pollution to the environment when burning. In addition, the processing process of magnesium hydroxide is short and the production cost is low. The market price is only half of aluminum hydroxide, but the flame retardant effect is equivalent to adding an equal amount of aluminum hydroxide.
In addition, the magnesium hydroxide after the doubling agent modified can increase its addition in its polyester glass fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber fiber, which helps increase the oxygen index value and further reduce the cost. And it is also feasible to use magnesium hydroxide as a flame retardant for polyester glass reinforcement.