预聚体对无溶剂聚氨酯胶黏剂耐蒸煮性能的影响

    Effects of Prepolymer on the Cooking-resistant Properties of Solvent-free Polyurethane Adhesives

    • 摘要: 本文合成了系列聚氨酯预聚体,将其用于制备双组分无溶剂聚氨酯胶黏剂,并利用红外光谱和核磁共振波谱证明预聚体和胶黏剂的结构。通过控制变量法研究了聚氨酯预聚体的异氰酸酯基质量分数(ωNCO)、多元醇分子量、R值(胶黏剂中–OH和–NCO基团的摩尔比)对胶黏剂黏度和耐蒸煮性能的影响。结果表明,在ωNCO为17%时,预聚体黏度较低,聚氨酯胶黏剂经水煮后的剥离力较高。当ωNCO一定时,随着多元醇分子量减小,预聚体黏度增大,聚氨酯胶黏剂水煮前后的剥离力增加。在多元醇分子量为1 609 g/mol,ωNCO为17%,R值为2.5时,水煮前后耐蒸煮聚丙烯流延膜层剥离力最高分别达到6.30 N和4.37 N。将该预聚体与多种B组分混合获得一系列聚氨酯胶黏剂,均满足国家标准GB/T 41168-2021对铝塑复合膜耐蒸煮性能的需求。

       

      Abstract: A series of polyurethane prepolymers were designed and synthesized as isocyanate-terminated component for the final product: two-component solvent-free polyurethane adhesives. Structural characterization using infrared and 1H NMR spectroscopies confirmed the structure of the designed prepolymers. The effect of the isocyanate mass fraction (ωNCO) of the prepolymer, molecular weight of polyols and ratio R (molar ratio of –OH to –NCO in adhesives) on viscosity and cooking resistance of the polyurethane adhesives were investigated by a variable-control method. The results show that in the case of ωNCO=17%, the prepolymer has a low viscosity, and the prepared adhesive has a higher peel force after boiling treatment. For a constant value of ωNCO, as the molecular weight of the polyol decreases, the viscosity of the prepolymer increases, so does the peel force of the polyurethane adhesive before and after boiling. With polyols molecular weight of 1 609 g/mol, ωNCO of 17% and R of 2.5, the peel force of retort cast polypropylene (RCPP) layer before and after boiling is as high as 6.30 N and 4.37 N, respectively. A series of polyurethane adhesives were prepared by mixing this prepolymer with different B components, meeting the requirements in standard GB/T41168-2021 for cooking resistance requirements of aluminum plastic composite film.

       

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