EPA with unsaturated aliphatic straight chain is used to modify PF resin

in which methylene is displaced by unsaturated aliphatic straight chain.The modified PF resin possesses a higher strength and lower decomposition temperature than the tranditional PF resin does.The effects of EPA addition on the resin properties and mechanical properties of the coated sand were investigated.It was showed that the 10% adddition is an optimum value.Heat-zero gravity and bending curves at high temperature results showed that the coated sand mixed by the resin was characteried by high strength and good collapsibility.Pouring experience with the collapsible coated sand showed that the time of clean work was shortened and efficiency was significantly increased.