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Evaluation of different halogen-free flame retardants in polypropylene formulations as alternatives to flame retardants containing halogens.


This document concerns an evaluation of several halogen-free flame retardants. The evaluation also presents some new types of flame retardants which are fully functional, commercially available and cost-efficient alternatives to traditional halogenated flame retardants. The details, strengths and limitations of all alternatives are listed below.

Substituted substance(s)

  1. DecaBDE

    CAS No. 1163-19-5 EC No. 214-604-9 Index No. 
  2. Hexabromocyclododecane (HBCDD)

    CAS No. 3194-55-6, 25637-99-4 EC No. 221-695-9, 247-148-4 Index No. 
  3. Tetrabromobisphenol A (TBBPA)

    CAS No. 79-94-7 EC No. 201-236-9 Index No. 604-074-00-0

Alternative substance(s)

  1. Phosphorus (red)

    CAS No. 7723-14-0 EC No. 231-768-7 Index No. 015-002-00-7
  2. Aluminium hydroxide

    CAS No. 21645-51-2 EC No. 244-492-7 Index No. 
  3. Expandable graphite

    CAS No.  EC No.  Index No. 
  4. Molybdates

    CAS No.  EC No.  Index No. 
  5. Magnesium hydroxide

    CAS No. 1309-42-8 EC No. 215-170-3 Index No. 
  6. Borates

    CAS No.  EC No.  Index No. 
  7. Organoclays

    CAS No.  EC No.  Index No. 

Other type of alternative

Reliability of information

Internet information: data are from an internet document and only a basic and partial evaluation could be performed

Hazard assessment

None of the alternatives described as alternatives substance above are present at the SUBSPORT Database Selection Criteria (SDSC). Red phosphorus is however classified as R11, R16 and R52/53 which means that the compound is flammable and even explosive. It may also cause adverse effect in the aquatic environment.
The possible adverse effects of several of the halogenated flame retardants that these additive formulations could substitute is however far greater since many of the halogenated flame retardant have PBT-properties.

» Check the Substance Database according to SUBSPORT Screening Criteria (SDSC)

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Substitution description

The substitutions detailed in this case study describes different ways to improve flame retardancy in polypropylene formulations. The aim of the study is to reduce flame retardants based on halogen containing compounds.

Previous studies by the same author has concluded that the easiest way to improve flame retardancy in a material is to add suitable additives to the polymeric material. In the study described here; 18 different additive formulations were tested for their flame retardant properties. The study was made by the Swedish Civil Contingencies Agency in cooperation with a company manufacturing plastics: PP Polymer. All the recipes used in the experiment are the property of PP Polymer and therefore only the main ingredients and not the full recipe will be shown in this case study. The main ingredients in the different additive formulations are: N-P compounds, red phosphorus, expandable graphite, conventional aluminum hydroxide (ATH), magnesium hydroxide, molybdates, borates and organoclays in different concentrations.

The different additive formulations were tested on their properties concerning density, thermal degradation, heat deformation and visco-elastic properties. The results showed that the additive formulations worked well and that flame retardant materials without halogens could be made without affecting the manufacturing process or the properties of the material. Since all ingredients are commercially available, it was estimated that a flame retardant polypropylene based on any of the additive formulations tested in this report would not be significantly more expensive than the flame retardants available on the market presently.

Please note that all recipes are owned by PP Polymer AB. For specific questions regarding ingredients use the contact information provided below.

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Case/substitution evaluation

Negative aspects of many of the most commonly used halogenated flame retardants have been observed for a long time. Alternatives that provide the same amount of flame retardancy but with less negative effects on the environment are therefore important. The alternatives described here does not contain any halogens and are not individually considered dangerous to the environment making them a promising alternative. A full evaluation is however difficult to do since not all ingredients are known to us.

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Other solutions

Further information

Further languages available

Who provided the information

Type of information supplier
Producer / distributor


The report which this case study has been based on have been prepared by the Swedish company PP Polymer on behalf of the Swedish Civil Contingencies Agency.

Swedish Civil Contingencies Agency

Switchboard: +46 (0) 771-240 240
Fax: +46 (0) 10-240 56 00


Publication source

The report which this case study has been based on have been prepared by the Swedish company PP Polymer on behalf of the Swedish Civil Contingencies Agency.

PP Polymer

PP Polymer AB
Box 191
tel:  +46(0)8-44 55 300
fax: +46(0)8-44 55 309


Swedish Civil Contingencies Agency

Switchboard: +46 (0) 771-240 240
Fax: +46 (0) 10-240 56 00

Type of publication and availability 

Freely available

Original document: click here

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