n propyl bromide as a coatings solvent

Citation

Bean, J. (1998), "n propyl bromide as a coatings solvent", Pigment & Resin Technology, Vol. 27 No. 6. https://doi.org/10.1108/prt.1998.12927faa.003

n propyl bromide as a coatings solvent

n propyl bromide as a coatings solvent

Coatings applicators are now constantly looking to the coatings manufacturers to come up with alternative solvents to those now outlawed, or restricted in use, by environmental legislation. In particular they would like to find a permissible alternative to 1,1,1-trichloroethane for cleaning components prior to painting.

Some are putting their faith in n propyl bromide. However, an interesting article by Barry Eaton of SIS Chemicals published in the August issue of Finishing suggests that n propyl bromide may not be the panacea for solvent use. A main reason, and one that has led the manufacturers to be cautious with claims on its use, is that although some tests have been carried out, there is a list of toxicological tests still to be undertaken. In addition there is a risk that the material will behave in a similar way to iso propyl bromide, which is now considered to be linked to reproductive abnormalities.

He also draws attention to the conflicting exposure limits recommended by the manufactuers of the solvent. One says it has a 200ppm exposure limit, whilst others say 100ppm. Barry Eaton says that the ozone depletion potential (odp) of n propyl bromide is another area surrounded by doubt. There are apparently two studies which have been accepted by the US EPA. One says that the odp is 0.006 while the other says 0.26, which is higher than that of HCFC 225 which is banned for cold cleaning in Europe because of its odp.

It may turn out that when all tests are completed n propyl bromide can be used as a completely safe solvent and a good alternative to 1,1,1-trichloroethane. We agree that until then users should exercise a degree of caution.

John Bean