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US 4,395,542 AGranted
Process for removing trace amounts of epichlorohydrin from heat sensitive glycidyl products
AssigneeCiba-Geigy Corporation
InventorYel S. Sury
Life of this patent
Estimating the term…
Abstract
Epichlorohydrin levels in heat sensitive glycidyl products are reduced from a few thousand ppm, an unacceptable level, to only a few ppm or to a non-detectable level by use of a multistage stripping column with or without inert gas purging without decomposition of the heat sensitive glycidyl products. Such glycidyl products are useful in epoxy resins particularly as crosslinking agents.
Claims10
A method of preparing an epoxy resin or product containing glycidyl groups, essentially free of residual epichlorohydrin and associated volatile material, which comprises
- heating an epoxy resin or product containing glycidyl groups, which still contains excessive amounts of residual epichlorohydrin and associated volatile materials, to a temperature of 60.degree. to 250.degree. C., a temperature sufficient to allow said resin or said product to flow easily, but insufficient to cause thermal decomposition thereof, and
- passing the heated resin or product one or more times through a packed column or multistage evaporation stripper, to effect multistage stripping of said resin or product, at a temperature of 60.degree. to 250.degree. C. and at a pressure of 1 to 500 mm Hg, to reduce the level of epichlorohydrin and associated volatile materials in the heated resin or product to less than 10 ppm.
Dependencies are inferred from the claim text.