Study of Resin-bonded Calcia Investment

Part 1. Setting Time and Compressive Strength

抄録

This study was carried out to develop a new titanium casting investment consisting of calcia as the refractory material and a cold-curing resin system as the binder. The setting time of the investment was investigated under different N, N-dimethyl-p-toluidine (DMPT) contents in methyl methacrylate monomer (MMA) and benzoyl peroxide (BPO) contents in calcia without any sintering agent. The effects of the sintering agents, which were calcium fluoride (CaF₂) and calcium chloride (CaCl₂), on the compressive strength of the investments were investigated at room temperature before and after heating to two different temperatures. The shortest setting time (68 minutes) of the investment was obtained at 0.37 DMPT/BPO (1.5vol%/1.0 mass%) ratio by mass. The highest strength (16.5MPa) was obtained from the investment which contained 2 mass% CaF₂ and was heated to 1, 100°C. It was found that the developed calcia investment containing 2 mass% CaF₂ has a possibility for use in titanium castings.