什么是反应型热熔胶？ -pg电子试玩入口
反应型热熔是融热熔和反应型胶黏剂性能为一体的胶黏剂。它是在热塑性树脂分子中引入可反应的活性基团，用其组成的hm在涂覆于被粘体后通过活性基因反应使之交联固化形成热固性树脂，从而提高粘接强度、耐药性以及耐蠕变等特性。
反应型热熔胶无，室温下为单组分固态物质，使用前加热到熔融状态，然后以一种热的黏性状分散到结构件上，当涂好的基质冷却至室温时粘接连接强度迅速增加，胶黏剂与吸附在涂好的结构件中的湿气反应形成高度关联的网状物质。固化后的结构件比传统的单组分热熔胶显示出更好的耐热性。但初粘强度不如传统热熔胶。
反应热熔胶需加热成液态才可喷涂到被粘面，从而增加了操作难度和费用。如何使其在常温下就保持液态，此课题具有较强的实用价值和经济价值。
理想的反应型热熔胶应具有高的初粘强度，快速固化且熔融稳定，好的粘接性能和优异的耐热性。而提高固化速率和保持熔融稳定性是相反的因素，解决这一问题的关键是选择合适的。目前作为反应型热熔胶的主体材料多为一nco封端的聚氨酯，所用的催化剂有机锡、有机胺及一些专用催化剂，在交联过程中，由热塑性转为热固性。在配方中长常加入其他物质以满足特殊要求，如黏流性、强度、敞开时间、阻燃性，加入热塑性聚合物，以增加软化性和流动性，这种purhm广泛应用于外包装、机械改造和办公的制造上。
另一类反应热熔胶分为高分子量，其在特殊固化剂存在下，环氧基可开环而进行分子内交联，得到强度大、耐热性好的粘接效果。甲基酚醛树脂亦可再加热条件下与固化剂反应而成为反应型热熔胶。而酸性条件下制得的线型酚醛树脂只能作为一般热熔胶使用。水解性有机硅烷化合物也可作为反应型热熔胶用于粘接玻璃、皮革、金属。
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kyrgyzstan unfpa in the news
kyrgyzstan: youth meet on world aids day
multiple media outlets reported on 6 december that members of the regional youth team "red ribbon," popular kyrgyz singer kanykei, and representatives of the ngo youth peer education network (y peer) met with boarding school students as part of world aids campaign 2013.
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