水性封闭型异氰酸酯交联剂的制备及其在表面施胶中的应用

Preparation of Waterborne Blocked Isocyanate Crosslinking Agent and Its Application in Surface Sizing

中文关键词:  封闭型异氰酸酯  表面施胶  耐折度  抗张指数

Key Words:blocked isocyanate  surface sizing  folding endurance  tensile index

中文摘要:

      以异佛尔酮二异氰酸酯（IPDI）和1，4-丁二醇（BDO）为原料，2，2-二羟甲基丙酸（DMPA）为扩链剂，N-甲基-2-吡咯烷酮（NMP）为溶剂，采用一步法制备聚氨酯预聚体，随后采用丁酮肟（MEKO）对预聚体进行封端反应，经有机碱中和并加水乳化，制得水性封闭型异氰酸酯交联剂（WBIC）。将制得的WBIC与聚乙烯醇（PVA1799）进行复配，在一定温度下对纸张进行施胶并在约110℃进行解封反应。通过傅里叶变换红外光谱（FI-TR）、热重分析（TGA）及乳液稳定性等测试，对样品结构及稳定性进行分析并对施胶后纸张进行物理性能测试。结果表明，当R值（—NCO/—OH）为1.8且以MEKO封端时，制得的乳液稳定且粒径最小，为85.14 nm，聚合物分散系数（PDI）为0.171。施胶后纸张物理性能大幅提高，与原纸相比，耐折度、抗张指数、挺度、撕裂指数和耐破指数分别提高了57.6%、29.1%、165.4%、31.0%和59.0%；施胶后纸张接触角为96°。

Abstract:

      The polyurethane prepolymer， prepared through one-step method using isophorone diisocyanate （IPDI） and 1，4-butanediol （BDO） as raw materials， 2，2-dimethylolpropionic acid （DMPA） as chain extender， and N-methyl-2-pyrrolidone （NMP） as solvent， and further blocked by 2-butanone oxime （MEKO）， was eventually neutralized using organic base and emulsified with water to prepare a waterborne blocked isocyanate crosslinking agent （WBIC）； which was compounded with polyvinyl alcohol （PVA1799） to size paper at certain temperature and unblocking reaction was subsequently conducted at ~110℃. Fourier Infrared Spectroscopy （FI-TR）， thermogravimetric analysis （TGA）， and emulsion stability tests were conducted to analyze the structure and stability of the prepared samples， and physical properties of the sized paper were tested as well. The results showed that the prepared emulsion was stable with the smallest particle size of 85.14 nm， polymer dispersion index （PDI） of 0.171 when R value （—NCO/—OH） was 1.8 and MEKO used as blocking agent. Compared with base paper， physical properties of the sized paper increased greatly with folding endurance， tensile index， stiffness， tearing index， and bursting index increased by 57.6%， 29.1%， 165.4%， 31.0%， and 59.0%， respectively； the contact angle of sized paper was 96°.