High Performance Bisphenol A (BPA)-Free Epoxy Resins

TURI Research Report No. 66. 

The purpose of this research was to synthesize a Bisphenol A (BPA) free epoxy resin
in order to replace existing BPA containing epoxy resins such as liquid
Bisphenol A diglycidyl ether (BADGE) and related high molecular weight
BPA-based solid epoxies. This represents an important step in the development
of BPA free epoxy liners for food and beverage cans and would eliminate the
health concerns associated with BPA-based epoxy can liners currently used in
food packaging. The epoxy resin in question, 2,2,4,4-tetramethyl-1,3-cyclobutanediol
diglycidyl ether (CBDO-DGE), was synthesized via the reaction of  2,2,4,4-tetramethyl-1,3-cyclobutanediol
(CBDO) with epichlorohydrin using tetrabutylammonium hydrogen sulfate (TBAB) as
the phase transfer catalyst under basic conditions. Nuclear magnetic resonance
(NMR) spectroscopy of the reaction product produced results consistent with
successful CBDO-DGE synthesis, a conclusion confirmed by its successful
crosslinking using triethylenetetramine (TETA). The curing reactions and
thermal properties of the epoxy resin were analyzed in comparison with a
conventional BADGE/TETA system.  As its purity was improved, the synthesized CBDO-DGE product yielded thermal
properties approaching those of the BADGE material.