绝缘纸耐热助剂的制备及应用研究

Study on Preparation and Application of Heat-resistant Additives for Insulating Paper

关键词:  封闭型水性聚氨酯  耐热助剂  绝缘纸  热老化

Key Words:blocked waterborne polyurethane  heat-resistant additive  insulating paper  thermal aging

摘要:以甲乙酮肟为封闭剂，异佛尔酮二异氰酸酯、聚乙二醇-400为主要原料，合成了封闭型水性聚氨酯（WPU）耐热助剂，采用傅里叶变换红外光谱仪对WPU分子结构进行表征。将WPU应用于绝缘纸浸渍处理制备耐热绝缘纸，对绝缘纸、耐热绝缘纸在150℃条件下进行0～168 h的热老化实验，对纸张热老化前后的抗张强度、纤维素聚合度和纤维表面形貌进行表征。红外光谱结果表明，WPU在130℃下发生解封反应，释放出与纤维素羟基反应的异氰酸酯基团，形成WPU与纤维的交联网络结构。相比绝缘纸，在热老化过程中，耐热绝缘纸的纤维素聚合度下降速率低于绝缘纸，抗张强度损失率由38.5%降低至19.8%，WPU可以显著提高绝缘纸的耐热老化性能。

Abstract:A blocked waterborne polyurethane （WPU） heat-resistant additive was synthesized with methyl-ketoxime as blocking agent， isophorone diisocyanate and polyethylene glycol 400 as the main raw materials. The molecular structure of the WPU was characterized by FT-IR. The WPU was applied to the impregnation treatment of insulating paper to produce heat-resistant insulating paper. The thermal aging experiments of untreated insulating paper and WPU-treated insulating paper were conducted at 150℃ for 0～168 h. Then the tensile strength， polymerization degree of the cellulose and fiber surface morphology of the insulating paper before and after the thermal aging were studied. The results showed that the CPU deblocks at 130℃ and releases the isocyanate group which reacted with the cellulose hydroxyl group to form the crosslinked network structure between the WPU and the fiber.In the process of thermal aging， the cellulose polymerization degree of WPU-treated insulating paper was lower than that of untreated insulating paper， and the loss rate of tensile strength decreased from 38.5% to 19.8%， WPU could significantly improve the thermal aging resistance of insulating paper.