Non-Halogenated Flame Retardant

NineSigma, representing Synthos SA, one of the world's leading producers of expanded polystyrene (EPS), invites proposals for suitable halogen-free compounds which, when added to EPS during the manufacturing process, will impart flame retardant properties.

Amongst many other uses, expandable polystyrene (EPS) can be used as an insulation material within buildings. In order to ensure that the material is safe to use in such an application, legislation requires that EPS designed for building use conforms to certain standards, including a standard for flame resistance.

Synthos currently produces EPS which complies with the building regulations for the markets that it supplies to. As part of the suspension polymerization manufacturing process which Synthos uses, a flame retardant material is added that imparts the necessary properties to the base material.

Although the flame retardant that is currently used meets all of the technical requirements, it contains bromine, which is increasingly seen as harmful to the environment. Synthos is therefore seeking an alternative flame retardant that meets all of the technical requirements but does not contain bromine or any other halogen.

Synthos would also like to identify potential non-halogenated flame retardants that would allow it to offer its users improved environmental performance, either in terms of improved recyclability or reduced environmental impact.

Anticipated Proiect Phases

Phase 1 - Review proposals

• Seek additional information as required to properly evaluate each proposal. (A Non-Disclosure Agreement may be required in order that additional information can be shared, so that a full assessment can be made)

Phase 2 - Test proposed solution

• Tests to be conducted within Synthos' R&D facility
• It is anticipated that the duration of this second phase will very much depend upon the length of time required to prepare a flame retardant material that can be tested in the Synthos EPS suspension process

Criteria for Moving from Phase 1 to Phase 2

Synthos will consider the supplied evidence that the proposed solution could potentially meet their technical requirements and the likelihood that the solution could be cost-effective for a commodity product manufactured in very high volumes.

An assessment will also be made of the potential for using the proposed solution to offer additional environmentally-friendly benefits to users.

The successful technology will:

• Offer flame retardant properties for expandable polystyrene (EPS)
  • Be active in gas phase and solid phase
  • Be resistant to temperatures up to 300°C
  • Decomposition to start at a temperature above 250°C
  • Meet flame retardant specifications for EPS foams used within the building industry at a concentration below 1.5%
• Be suitable for the Synthos EPS manufacturing process
  • Easily miscible with monomer (styrene) and polymer (polystyrene), providing homogenous dispersions, preferably dissolving in monomer and polymer
  • Be inert for polymerization and does not interact with free radicals or react with peroxides and radical initiations
  • Melt or soften around 120°C
• Not be soluble in water

Desirable properties for the flame retardant:

• Be white or very light in colour (as close as possible to the natural, bright white colour of EPS)
• • Be resistant to UV degradation
  • Be resistant to thermo-oxidative degradation
  • Have a bulk density in the range 0.5-0.8 g/cm³
  • Other physical properties
  • Have a specific density in the range 1.5-2.0 g/cm³ 
• Have low environmental impact
  • Be biodegrade without the creation of toxic substances
  • Have a structure so as to prevent migration of the flame retardant with water into the environment
  • If migration could occur, have a molecule / oligo- or macromolecule which is non-pollutant, non­ hazardous, non-persistent, non-bioaccumulative and non-toxic
• Offer recycling opportunities
  • The EPS with flame retardant would be suitable for recycling via a compounding process or chemical process
  • The flame retardant could be extracted, separated, purified and used again
  • When recycled and used again in pure form or regranulate form, maintain its physical, chemical properties and flame retardancy