Halogen-antimony system, i.e., gas phase flame retardant mechanism. Commonly used halogen flame retardants are decabromodiphenyl ether, hexabromocyclododecane, octabromoether, tetrabromobisphenol A, etc., plus flame retardant synergist antimony trioxide, which has the characteristics of small addition amount and good flame retardant effect.

Types and characteristics of halogen flame retardants

Halogen flame retardants have always been criticized by green environmental protection organizations, and even restricted and banned in some countries. However, advanced countries such as the United States and Japan still allow their use. As a developing country, China still has a lifespan of at least ten years for halogen flame retardants.

Development of PP flame retardant technology

PP is treated with bromine-containing alkyl phosphate. This type of flame retardant has both P-Br synergistic effect, which makes the flame retardant effect significant. At the same time, it can also improve the rheological properties and processing properties of PP, and has little effect on the physical and mechanical properties of PP.

In recent years, the intumescent flame retardant pioneered by Professor Camino of the University of Turin, Italy, has played a huge role in PP flame retardant technology. This type of P-N flame retardant has high efficiency, high thermal and light stability, low toxicity, low smoke, low corrosion, little effect on processing and mechanical properties, and will not cause environmental pollution. In PP, only 25-30phr can be added to reach UL94 V-0 level.

The amount added to PE should reach 30-35phr, which can reach UL94 V-0 level. At present, there are many commercialized polyolefin halogen-free flame retardants in China. I believe that with the competition in the market, the grade of products will definitely be greatly improved!

Flame-retarded polypropylene of the graft copolymer of pentabromobenzyl acrylate and ethylene propylene rubber. This type of flame-retardant PP has high impact strength and can be used as engineering plastics in some occasions.

Inorganic filler flame retardant polypropylene, the so-called inorganic filler refers to aluminum hydroxide and magnesium hydroxide, which have the effects of flame retardancy and smoke suppression. However, to achieve the desired effect, micronization and surface treatment are key technologies that are applied to different plastics. The matching surfactant should be carefully selected to make it compatible with the plastic and evenly dispersed in the plastic without affecting the mechanical properties of the plastic too much.

Since ATH and magnesium hydroxide can play a flame retardant and smoke suppression role in different temperature ranges, the combination of the two can enable the plastic to continue to exert a flame retardant effect in a wider temperature range. When treating PP with magnesium hydroxide, in order to achieve better flame retardant effect and suitable mechanical properties, it is advisable to adopt a two-step feeding method in the mixing process of adding magnesium hydroxide, which will obtain better results than a single feeding.

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