封闭型水可分散性异氰酸酯改性丙烯酸酯的制备及应用

Preparation and application of a closed water-dispersible isocyanate modified acrylate

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,合成一种两亲性聚合物P(MPEG350A-co-BA-co-HPA),再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,将质量分数1%(以绝干浆质量计,下同)PAIM与质量分数4%聚乙烯醇(PVA)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应用性能对比。结果表明,当共聚物PAIM-3中n(MPEG350A)∶n(BA)=2.0∶1.0,w(HPA)=10.4%,w(—NCO)=7.9%,施胶剂质量分数为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·m^2/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、抗张指数、撕裂指数和挺度分别提高了29.3%、32.3%、22.1%和19.5%。

A closed water-dispersible isocyanate modified acrylate copolymer(PAIM)was gradually synthesized by solution polymerization.In which,an amphiphilic polymer P(MPEG350A-co-BA-co-HPA)was synthesized from methoxypolyethylene glycol acrylate(MPEG350A),butyl acrylate(BA)and hydroxypropyl acrylate(HPA),followed by condensed with isophorone diisocyanate(IPDI)and finally terminated by methyl ethyl ketoxime(MEKO).Then,a composite sizing agent(PMP)for sizing kapok mixed paper was prepared with PAIM with a mass fraction of 1%(based on the mass of dry pulp,the same below)and polyvinyl alcohol(PVA)with a mass fraction of 4%.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 on the particle size and stability of PAIM dispersion were discussed by DLS and TSI.The effect of isocyanate content on the physical properties of paper was studied.The application performance of PMP was compared with that of the commercial sizing agent.The results showed that when n(MPEG350A)∶n(BA)=2.0∶1.0,w(HPA)=10.4%,w(—NCO)=7.9%,the sizing agent PAIM-3 had excellent performances.When mass fraction of sizing agent PAIM-3 was 10%,the folding endurance,tensile index,tear index,stiffness and contact angle of paper were 569 times,66.83 N·m/g,11.54 mN·m^2/g,92.16 mN,and 80.3°,respectively.Compared with commercially available sizing agent,PMP-3 had a longer storage period.After PMP-3 sizing,the paper folding resistance,tensile strength,tearing degree and stiffness were increased by 29.3%,32.3%,22.1%and 19.5%,respectively.