n.密封劑；密封層
If the discoloration is the joints, please remove the sealant that used in craft completely. 如果是接縫處的變色，必須將連接處密封劑完全去除。
A summary of the research of low monol polyether polyols polyurethane sealant is given. 總結(jié)了低單聚醚聚氨酯密封劑的研制。
密封膠
