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Several issues that should be noted in the use of halogen-free flame retardants


Release time:

Sep 26,2021

[Summary]Generally speaking, with the decrease of the amount of PP and the increase of the amount of halogen-free flame retardant, the flame retardant effect of the material will get better and better. Why is the PP in glass fiber relatively reduced (adding glass fiber), the amount of halogen-free flame retardant unchanged, and the flame retardant will become worse or even unchanged? This is mainly because the addition of glass fiber destroys the flame retardant mechanism of the expansion system, glass fiber is distributed in various parts of the plastic, the carbon layer closed has a great destructive effect, so that it can not be achieved by isolating oxygen.

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

Generally speaking, with the decrease of the amount of PP and the increase of the amount of halogen-free flame retardant, the flame retardant effect of the material will get better and better. Why is the PP in glass fiber relatively reduced (adding glass fiber), the amount of halogen-free flame retardant unchanged, and the flame retardant will become worse or even unchanged? This is mainly because the addition of glass fiber destroys the flame retardant mechanism of the expansion system, glass fiber is distributed in various parts of the plastic, the carbon layer closed has a great destructive effect, so that it can not be achieved by isolating oxygen.

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

In order to reduce costs, many manufacturers have added some fillers, such as calcium carbonate, barium sulfate, talc, etc., to the intumescent halogen-free flame retardant of the P N system, and found that the flame retardant effect will be lost. Similarly, the addition of the above-mentioned filler changes the esterification reaction process, the acid source partially reacts with the above-mentioned filler, and the above-mentioned filler destroys the formation of the carbon layer on the surface of the material, resulting in the failure of the mechanism. Similarly, the addition of some carbon black and toner will also lead to the loss of flame retardant effect.

  3. Why is there oil or powder on the surface of PP produced by some halogen-free flame retardants after being placed for a period of time (dozens of days)?

As we mentioned, the composition of halogen-free flame retardants consists of a carbon source, an acid source and a gas source, which inevitably leads to the precipitation of substances. One or more of the above substances are water-soluble and have poor compatibility with plastics. During the processing, the material and the above-mentioned powder are dispersed by the strong mechanical force of the screw machine. After being placed for a period of time, the substances of different polarities will slowly separate due to the continuous movement between molecules, and the above-mentioned powder will slowly precipitate from the inside of the material. To the surface.

  Why do some halogen-free flame retardants bubble or turn gray during PP processing?

Any halogen-free flame retardant has its initial decomposition temperature. If the decomposition temperature of the halogen-free flame retardant itself is only close to the melting temperature of the material, it is easy to appear. Therefore, in general, the initial decomposition temperature of the halogen-free flame retardant At least 50 degrees higher than the temperature of the material plasticizing process, so as to ensure the smooth progress of the process.

 

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