n.密封剂；密封层
If the discoloration is the joints, please remove the sealant that used in craft completely. 如果是接缝处的变色，必须将连接处密封剂完全去除。
A summary of the research of low monol polyether polyols polyurethane sealant is given. 总结了低单聚醚聚氨酯密封剂的研制。
密封胶
