Bac2 catalyst used to develop storage-stable phenolic and furan BMC and SMC for fire-retardant moulded composites
Southampton, UK, June 28, 2011: Bac2, the cleantech materials and components company, has developed its CSR family of latent acid catalysts to create formulations suitable for production of stable phenolic and furan-based pre-polymeric mixes. These inherently flame-retardant bulk and sheet moulding compounds (BMCs and SMCs) maintain good mould-flow characteristics and can be cured rapidly at 120 degrees C or more slowly at temperatures above 50 degrees C. Applications requiring flame-retardant mouldings include interior fittings for all forms of transportation, seating for stadia, electrical insulation products, and electronic/electrical systems packaging.
Most BMCs and SMCs use polyester-based resins that require the addition of fillers in order achieve flame-retardancy. At one time, chlorinated or brominated flame-retardants were commonly used but these have now been banned in many parts of the world, in part due to the large amount of toxic smoke they generate when exposed to flames. Alternative additives include aluminium trihydrate, ammonium polyphosphate and antimony oxide but these affect the structure of polyester resins, make them harder to mould, and are detrimental to the quality of finished products.
CSR latent catalysts are used with established phenolic resoles which meet the fire, smoke and toxicity requirements for mass transit, marine, offshore and construction applications. These resins are normally employed in hand lamination processes, spray deposition, continuous lamination and syntactic foam, all of which are processes where the pot life or working life of the resin and catalyst do not prevent the successful composite part production. However, for bulk moulding and sheet moulding compounds the existing catalysts are not capable of producing a moulding compound with a storage life of more than 3-4 hours. For that reason, phenolic resole resins have not been employed in BMC or SMC.
CSR latent acid catalysts however can be used with established phenolic resoles and reactive furan resins to give storage-stable moulding compounds more than 3 months’ shelf life at room temperature. For the first time, one-pack, phenolic-based and furan-based compounds are available for the production of inherently flame-retardant mouldings. Bac2 has demonstrated that when using CSR catalysts, the processing properties and the composite properties of moulded products are not significantly different if curing is carried out immediately after preparing the pre-polymeric mix or several months later.
Bac2 offers a choice of standard CSR latent acid catalyst products, and works with customers to develop specific catalyst-resin package for the particular process requirements. The company also licenses the catalyst to partners for further development. Bac2 developed the CSR catalyst technology for use in the manufacture of compression moulded fuel cell plates.