聚丙二醇分子量对聚氨酯在油墨中应用性能的影响

Influence of Polyol Molecular Weight on the Application Performance of Polyurethane in Ink

目的研究具有良好应用前景的醇溶性聚氨酯油墨,并探究聚氨酯单体的分子量所合成的连接料对油墨印刷适性和触变性的影响。方法采用扩链反应和预聚合的方法,以甲苯二异氰酸酯(TDI)、聚丙二醇(PPG,数均分子量Mn为1000,1500,2000,3000,4000)和扩链剂2,2-二羟甲基丙酸(DMPA)为原料,合成一系列醇溶性聚氨酯(PU1000,PU1500,PU2000,PU3000,PU4000),用傅里叶红外光谱(FTIR)和凝胶渗透色谱(GPC)对其结构进行定性分析。研究不同分子量PPG合成的聚氨酯作为连接料对油墨的粘度、细度、印刷适性、油墨的稳态剪切粘度和触变性的影响。结果不同分子量PPG合成的聚氨酯连接料对油墨的各项性能有重要影响,随着PPG分子量的逐渐增大,油墨的粘度、细度和稳态剪切粘度先增大后减小。当Mn=1500时,所合成聚氨酯制备的油墨综合性能最佳,油墨粘度为880 MPa·s,细度为5μm,析油率为5%,具有良好的印刷适性(附着力为93%,初干性为84 mm/s,光泽度为37),油墨在15s的结构回复率为94.47%,触变性良好。结论将所合成的聚氨酯作为连接料,在油墨中具有较好的应用前景。

The work aims to develop alcohol-soluble polyurethane ink with good application prospects, and to explore the influence of the binder synthesized by the molecular weight of the polyurethane monomer on the printability and thixotropy of the ink. Toluene diisocyanate(TDI), polypropylene glycol(PPG, Mn=1000, 1500, 2000, 3000, 4000) and chain extender, 2,2-dimethylolpropionic acid(DMPA) were used as raw materials to synthesize a series of alcohol-soluble polyurethanes(PU1000, PU1500, PU2000, PU3000, PU4000) through chain extension reaction and pre-polymerization. Then, Fourier infrared spectroscopy(FTIR) and gel permeation chromatography(GPC) were adopted to analyze the structure of alcohol-soluble polyurethanes qualitatively. Finally, the influence of polyurethanes, as the binder, synthesized by PPG with different molecular weightson the viscosity, fineness, printability, steady shear viscosity and thixotropy of ink was investigated. The polyurethane binder synthesized by PPG with different molecular weights had an important influence on the properties of ink. With the increase of molecular weight of PPG, the viscosity, fineness and steady shear viscosity of ink firstly increased and then decreased. When Mn=1500, the ink prepared by the synthesized polyurethane had the best comprehensive properties, such as viscosity of 880 MPa·s, fineness of 5 μm, oil separation rate less than 5%, superior printability(adhesion of 93%, initial dryness of 84 mm/s and gloss of 37) and excellent thixotropy(structure recovery rate of 94.47% at 15 s). The proposed polyurethane will have good application prospect in ink as the binder.