Polypropylene is a thermoplastic resin made by the polymerization of propylene. There are three types of isotactic polypropylene, random polypropylene and syndiotactic polypropylene according to the arrangement of methyl groups. Experts in polylithic chemistry explain for you: the basic knowledge of flame retardant polypropylene. Flame retardant polypropylene materials can be divided into the following five categories:
① Halogen-antimony system, that is, the gas phase flame retardant mechanism. Commonly used halogen-based flame retardants are decabromodiphenyl ether, hexabromocyclododecane, octabromoether, tetrabromobisphenol A, etc. Good burning effect. However, halogen flame retardants have been criticized by green environmental protection organizations, and have even been restricted in some countries, and have been banned from use. However, the United States, Japan and other countries are still allowed to use, then as a developing country, the life of halogen-based flame retardants is at least 10 years.
② PP is treated with bromoalkyl phosphate. This type of flame retardant has the synergistic effect of PBr, which makes the flame retardant effect significant. At the same time, it can improve the rheology and processing properties of PP, and it has little effect on the physical and mechanical properties of PP.
③ PN flame retardant system. In the past ten years, the intumescent flame retardant pioneered by Professor Camino of the University of Turin in Italy has played a huge role in PP flame retardant technology.This type of PN flame retardant has high efficiency, high thermal and light stability, low toxicity, and low Smoke, low corrosion, small impact on processing and mechanical properties, will not cause environmental pollution. Just add 25-30 parts in PP to reach UL94V0 level. There have just been reports of the production of intumescent flame retardant products in China.
④ Graft copolymer of pentabromobenzyl acrylate and EPDM rubber flame-retardant polypropylene. This kind of flame retardant PP has high impact strength and can be used as engineering plastics in some occasions.
⑤ Flame retardant inorganic filler. The so-called inorganic fillers refer to aluminum hydroxide and magnesium hydroxide, which have the functions of flame retardancy and smoke suppression. However, to achieve the desired effect, micronization and surface treatment are the key technologies, which are applied to different plastics. It is necessary to carefully choose a matching surfactant to make it compatible with plastics and to be uniformly dispersed in the plastics without affecting the mechanical properties of the plastics too much. Because ATH and magnesium hydroxide can play the role of flame retardant and smoke suppression in different temperature ranges, the combined use of the two can make the plastics play a continuous flame retardant effect in a wide temperature range. It should be emphasized here that, in the treatment of PP with magnesium hydroxide, in order to achieve better flame retardant effect and appropriate mechanical properties, in the mixing process of adding magnesium hydroxide, a two-step feeding method should be used, which will obtain a ratio Better results with one feed.