Reactive Diluents

The technique of reducing the viscosity of an epoxy of an epoxy adhesive by adding a reactive diluents is a low viscosity liquid that is capable of combining chemically with the resin/hardener system. The reactive groups are usually epoxide and many reactive diluents are glycidyl ethers. In some cases the compounds many themselves form useful adhesive; generally speaking they do not.

Those reactive diluents that after comparative evaluation have been classed as high efficiency diluents” include allyl and butyl glycidyl ether, octylene oxide. Others that are used include 1,4-butanediol diglycidyl ether, phenyl and cresyl glycidyl ethers. Some of the paracid epoxidised cyclo-olefines referred to other article, such as butadiene dioxide, and limonene dioxide are useful reaction diluents.

Reactive diluents, being low molecular weight liquids with a relarively high epoxide content, are in some cases rather unpleasant to handle and are toxic. In this connection, however, it is reported that some of the olefine (and terpene) oxides, for example, limonene dioxide, dodecene oxide, octylene oxide, and a-pinene oxide are of a low order of toxicity.

A few epoxy resin compositions are marketed containing a proportion of reactive diluent, but normally the addition is made by the user, especially in the case of adhesives.