Eight common problems when using glass fiber reinforced PP flame retardant-Halogen Free Flame Retardant for PP

1. Why is the effect of intumescent halogen-free flame retardant used in glass fiber PP worse?

Since the addition of glass fiber destroys the flame retardant mechanism of the P-N expansion system, the glass fiber is distributed in various places of the plastic, which has a great destructive effect on the closure of the carbon layer, so that it cannot isolate oxygen and achieve the flame retardant effect.

Halogen Free Flame Retardant for PP

2. Why does the intumescent halogen-free flame retardant lose its flame retardant effect after adding filler or other substances?

In order to reduce costs, many manufacturers add some fillers, such as calcium carbonate, barium sulfate, talc, etc., to the P-N intumescent halogen-free flame retardant, which will lose the flame retardant effect. Because the addition of the above filler changes the esterification reaction process, the acid source will partially react with the above filler, and the above filler destroys the formation of the carbon layer on the surface of the material, resulting in the failure of the mechanism.

3. Why does some PP produced with P-N flame retardants have oily or powdery substances on the surface after being placed for a period of time (ten days)?

The composition of the flame retardant we mentioned is composed of a carbon source, an acid source and a gas source, causing substances to precipitate as one or more of the above substances. The water solubility is better, and the compatibility with plastics becomes poor. , The material and the above-mentioned powder are dispersed by the strong mechanical force of the screw machine, and after a period of time, due to the continuous movement of the molecules, the substances with different polarities will gradually separate, and the above-mentioned powder will slowly separate from the inside of the material. Precipitate to the surface.

4. Why do some P-N flame retardants foam or turn gray during PP processing?

Any flame retardant has its initial decomposition temperature. If the decomposition temperature of the flame retardant itself is only close to the melting temperature of the material, the above situation is likely to occur. Therefore, in general, the initial decomposition temperature of the flame retardant should be at least 50 degrees higher than the temperature of the plasticizing process of the material to ensure the smooth progress of the process.

5. Why do some P-N flame retardants tend to stick to water when squeezed out of the sink?

The sliver is easy to stick to water because some components of the flame retardant are more water-soluble. When passing through the outlet of the screw machine, the sliver with a higher temperature touches the cold water tank, and the powder is easy to precipitate, so the ingredients in the flame retardant must be water Insoluble.

6. Adding the same amount of flame retardant to very different PP may have a difference in flame retardant effect?

The difference of PP matrix, such as homopolymer or copolymer PP, is different in flame retardancy due to the different internal ethylene content. Generally speaking, copolymer PP is more difficult to achieve flame retardancy than homo PP, so add flame retardant accordingly. The agent may be more.

7. It is often seen that someone directly uses a lighter to test the extruded spline to judge the flame retardancy of the material. There is a certain degree of rationality, but there are also certain limitations. Why?

Use a lighter to test the flame retardant of the product directly. For the halogen system, it is easier to judge, because the mechanism of the system determines the compactness of the product has little effect on the flame retardant effect. The same is true for the hydroxide system; but for nitrogen Phosphorus-based char formation is flame retardant. Due to the carbon formation mechanism, the compactness of the product is limited, and there may be some pores inside, which have side effects on carbon formation. After injection molding, the compactness of the product is greatly enhanced, and the carbon formation effect is more rapid. .

8. When using phosphorus and nitrogen intumescent flame retardant to flame retard PP and reach UL94V-0 flame retardant level, can the flame retardant level be reduced to UL94V-2 by reducing the amount of phosphorus and nitrogen intumescent flame retardant added

No, because the flame retardant mechanism of the nitrogen-phosphorus intumescent flame retardant is "carbon formation" and "foaming", so as to achieve the effects of heat insulation, oxygen barrier and flame retardancy. Therefore, reducing the amount of nitrogen and phosphorus intumescent flame retardants added will not form a complete char-forming and foaming layer, and will not have the effect of flame retardancy.