水分散性封闭型异氰酸酯基改性丙烯酸酯共聚物合成及表面施胶增强作用

Synthesis of water-dispersible blocked isocyanate modified acrylate copolymer and surface sizing enhancement

摘要:

采用溶液分步聚合法，以甲氧基聚乙二醇丙烯酸酯（MPEG350A）、丙烯酸丁酯（BA）、丙烯酸羟丙酯（HPA）为原料，合成一种两亲性丙烯酸酯长链，用异佛尔酮二异氰酸酯（IPDI）进行缩合，继而用甲乙酮肟（MEKO）封端，制得一种封闭型水可分散的异氰酸酯改性丙烯酸酯共聚物（PAIM）。而后，质量分数1%（以绝干浆质量计）PAIM与质量分数4%（以绝干浆质量计）聚乙烯醇（PVA）进行复配制得复合施胶剂（PMP），用于木棉混浆纸施胶。通过FTIR、GPC对PAIM结构进行了表征，利用DLS、TSI探讨了亲疏水单体比及HPA单体用量对PAIM分散液粒径及稳定性的影响，研究了异氰酸酯含量对纸张物理性能的影响，并与市售施胶剂进行了应用性能对比。结果表明：当共聚物中n(MPEG350A):n(BA)=2:1，w(HPA)=10.1%，w(—NCO)=17.3%，施胶浓度为10%时，纸张耐折度达569次，抗张指数为66.83 N·m/g，撕裂指数为11.54 mN·m2/g，挺度为92.16 mN，接触角达80.3°。与市售施胶剂对比，PMP-3具有较长的储存期，且经PMP-3施胶后，纸张耐折度、抗张强度、撕裂度和挺度分别提高了29.3%、32.3%、22.1%和19.5%，具有优秀的商业应用前景。

Abstract:

A closed water-dispersible isocyanate modified acrylate copolymer was gradually synthesized by solution polymerization. The polymer is based on amphiphilic properties acrylate long chain, which was synthesized from methoxypolyethylene glycol acrylate (MPEG350A), butyl acrylate (BA), hydroxypropyl acrylate (HPA). Subsequently, condensed with isophorone diisocyanate (IPDI) and finally blocked with methyl ethyl ketoxime (MEKO). Then, a composite sizing agent (PMP) was prepared with 1% wt PAIM and 4% wt polyvinyl alcohol (PVA), which was used for sizing kapok mixed paper. The structure of PAIM was characterized by FTIR and GPC, the effects of the ratio of hydrophilic and hydrophobic monomers and the amount of HPA monomer on the particle size and stability of PAIM dispersion were discussed using DLS and TSI. The effects of isocyanate content on the physical properties of paper were studied, and the application performance was compared with the commercial sizing agent. The results showed that when n(MPEG350A):n(BA)=2:1, w(HPA)=10.1%, w(—NCO)=17.3%, the sizing concentration was 10 %, the paper had a folding endurance of 569 time, a tensile index of 66.83 N·m/g, a tear index of 11.54 mN·m2/g, a stiffness of 92.16 mN, and a contact angle of 80.3°. Compared with the commercially available sizing agent, PMP-3 had a longer storage period. After PMP-3 sizing, paper folding resistance, tensile strength, tearing degree and stiffness were increased by 29.3% ，32.3% , 22.1% ，19.5%, PMP had excellent business application prospects.