轻合金覆膜砂专用酚醛树脂的开发研究

采用具有不饱和脂肪直链的EPA改性剂参与合成酚醛树脂，用不饱和脂肪直链段部分取代亚甲基键，使酚醛树脂具有高强度和较低温度分解的特性。研究了EPA的加入量对树脂性质和覆膜砂力学性能的影响，10％是最佳值。热失重试验和高温变形曲线试验结果证明，使用该树脂混制的覆膜砂，具有强度高、溃散性好等特点。实践证明：使用该种覆膜砂浇注铸件后，工人的清砂劳动量下降，工作效率显著提高。

Special PF Resin for Light-alloy Coated Sand

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.