Workability of Cold Setting Epoxy Resins

Abstract

It has been found in this study that a correlation exists, at 1 per cent level of significance, between logarithmic viscosity and consistency or the degree of easiness of taking out from a vessel for 35 kinds of epoxy resin system of liquid resins and hardeners at 4 and 20°C. The relationship, which can be expressed by the equation “Y=AX+B”, indicates that a good workability is obtainable at the viscosity under 50000cps.The usable minimum temperature was obtained by either interporation or extraporation of the straight line in the plots of logarithmic viscosities against the reciprocal of absolute temperatures to the value of log 50000cps. 10 kinds of the liquid resins and 18 kinds of hardeners have the usable minimum temperature under 9°C.The relation between viscosity and consistency or workability reveals that the widely-used liquid resins such as Epikote 828 have very poor workability at temperatures below 9°C but their workability can be improved sufficiently by the addition of a reactive diluent. In case of hardeners, some kinds of improved aromatic polyamines and some kinds of improved aliphatic polyamines have good workability at temperatures below 9°C.Furthermore, 10 kinds of liquid resins and 10 kinds of hardeners have good workability at temperatures below 9°C, because both the viscosity and its temperature dependence were small enough for these materials.