阻燃EVA热熔胶的制备及其在线缆修复中的应用研究

选取二乙基次膦酸铝、焦磷酸二三聚氰胺和氢氧化铝为阻燃剂，制备了用于老化线缆快速修复的阻燃乙烯-醋酸乙烯酯共聚物（EVA）热熔胶，并对热熔胶材料的阻燃性能及线缆修复后的阻燃性能和绝缘性能等进行了测试和表征。结果表明，当3种阻燃剂的质量比为1:1:3，总添加量为50%（质量分数，下同）时，阻燃热熔胶通过垂直燃烧测试UL 94 V-0级且测试过程中无滴落，极限氧指数为27.1%；与纯热熔胶相比，阻燃热熔胶的热释放速率和总热释放量均大幅降低，阻燃体系发挥了很好的协同阻燃作用；修复后线缆的体积电阻率为1.15×1015Ω·m，热熔胶在线缆表面具有良好的成膜性和黏附力，线缆弯折过程中热熔胶不开裂、不脱落；燃烧过程中，修复后的线缆表面形成了膨胀的炭层，能有效保护线缆。

Preparation of flame retardant EVA hot melt adhesive and its application in repairing cables

In this article， a flame⁃retardant ethylene⁃vinyl acetate copolymer （EVA） hot⁃melt adhesive for quickly repairing aging cables was prepared， and the aluminum diethylphosphinate， dimelamine pyrophosphate and aluminum hydroxide were selected as flame retardant additives. EVA hot melt adhesive passed UL 94 V⁃0 rating without dripping and the limiting oxygen index was 27.1 vol% when the total loading amount of flame retardants was 50 wt% with the mass ratio of the above three flame retardants was 1：1：3. Compared with the pure hot melt adhesive， the heat release rate and total heat release of the prepared flame retardant hot melt adhesive was greatly reduced， and the flame retarded system exerted excellent synergistic flame retardant effect. The volume resistivity of the repared cable reached 3.12×10¹⁵ Ω·m. Moreover， the hot⁃melt adhesive exhibited excellent film⁃forming and adhesion on cable surface， and it will not crack or fall off during the bending process of the repared cable. The intumescent char layer is gererated on the cable surface and it can effectively protect the cable during combustion.