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【问】我们在《建筑工人》第二期看到了“建筑业的万能胶——107胶”的文章。107胶对于我厂生产的大板装饰和修理很有用途。您能否告诉我们107胶的配合比和制造方法吗?(湖南彭代宗)【答】107胶的学名是聚乙烯醇缩甲醛胶,是聚乙烯醇与甲醛在酸性介质中缩聚而成的。聚乙烯醇含有较多羟基(-OH),因而有较大的亲水性。通过缩醛化反应,可使其中的羟基缩合成疏水性的缩醛基团,以改善其耐水性。后者随缩醛化度的增加而提高,当达到一定程度后,就不再溶于水,成为醇溶性产物。为了施工方
[Q] In the second installment of “Construction Workers”, we have seen the article “Architectural Adhesive-107 Adhesive”. 107 glue is very useful for the decoration and repair of large plates produced by our factory. Can you tell us the compounding ratio and manufacturing method of 107 gel? (Pang Daizong, Hunan) [Answer] The scientific name of 107 gel is polyvinylalcohol formal, which is polycondensation of polyvinyl alcohol and formaldehyde in acidic medium. Polyvinyl alcohol contains more hydroxyl groups (-OH) and therefore has greater hydrophilicity. Through the acetalization reaction, hydroxyl groups can be condensed into hydrophobic acetal groups to improve its water resistance. The latter increases with the degree of acetalization, and when it reaches a certain level, it does not dissolve in water and becomes an alcohol-soluble product. For the construction side