为改善聚醋酸乙烯乳液耐水性差的缺点，用硅烷偶联剂对其进行了改性，使其压缩剪切强度的干强度和湿强度均有显著的提高。
Using silane coupling agent to copolymer with vinyl acetate, the water resistance of the polyvinyl acetate emulsion is improved, and the compress strength is praised.
为减少砂芯在湿度较大环境中存放时的强度下降，可在混砂时加入抗湿剂或增加粘结剂中聚异氰酸酯的比例。
The decrease in strength of sand cores can be reduced by adding an anti-moisture agent or increasing proportion of polyisocyanate in the mixture when the cores is stored up …
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