Binder Formulation in EVA-wax system for Fused Deposition of Ceramics
Abstract
Blends in the ethylene vinyl acetate (EVA) - wax system have been evaluated as potential
binders.to be used in fused deposition of ceramics (FDC). In order to obtain good handling
strength, it was indicated that the melting point of the polymer needs to be lower than that of the
wax. In this context, it was shown that the melting point of the EVA decreases as the vinyl
acetate content in the copolymer increases. By measuring the viscosity as a macroscopic
property, it was shown that 20 % vinyl acetate-containing EVA is miscible in microcrystalline
wax up to, atleast, 30 %.Binders used in FDC need to have low viscosity and it was pointed out
that the slumping can be one main problem associated with binders with low viscosity. Thus,
thermolysis of wax at low temperature is suggested as a solution. The volumetric thermal
expansion and melt strength of an EVA-wax blend were displayed as a function of temperature,
in the form of a penetration test.