How to choose the right halogen-free flame retardant for Polypropylene(PP)?

Antimony-bromide flame retardant for flame retardant PP has been very mature. In recent years there has been an increasing demand for low-halogen or halogen-free, so here is a brief overview of the types of halogen-free (low-halogen) flame retardants that can be used for PP:

1. Ammonium polyphosphate (APP) +Triazine charring agent

This class of flame retardants is currently the main system for producing halogen-free flame retardant PP (UL94 V-0).

Advantages: high efficiency and cost-effective

Disadvantages: easy to precipitate, not resistant to shear, granulation with water slippery phenomenon

Recommended manufacturers and grades: Clariant AP , Novista PNPO , Budenheim Budit

2. Piperazine pyrophosphate + Melamine Pyrophosphate

This is a new type of efficient halogen-free flame retardant that has gradually matured in recent years. It is mainly used in reinforced and non-reinforced halogen-free flame retardant PP (UL94 V-0), especially in the glass fibre reinforced PP system, which has excellent shear resistance and processing performance.

Advantages: high efficiency, no precipitation, no water slippage, shear resistance, excellent UV stability.

Disadvantages: slightly higher cost

Recommended manufacturers and grades: Adeka FP-2100/2200/2500 , Novista PNPO-G0/G1/G3

3. Phosphorus-nitrogen-bromine composite flame retardants

This system is mainly used for low halogen flame retardant PP (UL94 V-2). It can be used for PP thin-walled products, spinning and film. Its halogen content is <1000ppm, and it is regarded as "halogen-free flame retardant" under some regulations.

Advantage: Low dosage 1-2%.

Disadvantage: only reach UL94 V-2

Recommended manufacturers and grades: Novista EFBPP101/102