Sunday, June 21, 2009

Non Flammable epoxy Resin

The glycidyl ethers, the epoxides of olefines are capable of homopolymerization but the homopolymers are not attractive as adhesives. The range of interesting resins that the peracid method of epoxidation makes possible leads one to think that the future will inevitably bring a valuable range of adhesives, with perhaps the important extremes of high strength with flexibility at the other.

The normal bisphenol A glycidyl ethers are flammable, the degree depending on the curing agent. In an adhesive, flammability is usually not important because the mass of adhesive in any one area is small, and only partially exposed, but it is possible that there are applications where non flammability is important.

The use of hardeners containing phosphorus or halogen atoms to adhesive compound, provided the stoichiometric proportion involves the addition of a sufficiently large quantity, can reduce flammability appreciably; chlorendic anhydride (six chlorine atoms) is an example. But the maximum effect can be obtained only by making the resin itself also non-flammable. It was early appreciated that the use of a halogenated form of bisphenol A such as tetrachloro or tetrabromo bisphenol A (the technical grade s a viscous liquid), would be a step in the right direction. Of recent years a more sophisticated approach has been made to the subject, and Porret and Leumann have synthesized and examined a number of new glycidyl ethers containing halogen or phosphorus atoms.

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