The Study On The Factors Of Stability And Rheology Of Gel Ink

In recent years,the production of writing pen in China stand in the first place in the world,which has made us become a large country of pen-making.however,because of the research and development technology of domestic gel ink is not yet become mature,high-end ink still depend on imports,Still not a strong country of pen-making.Therefore,Strengthening the technology development and independent innovation of gel ink,completing domestic production of high-quality ink is essential to achieve the dream of creating a country of strong pen-making.Firstly,the origin,performance characteristics,composition,preparation process,writing mechanism and research progress of gel ink were reviewed,Subsequently,it pointed out that the current development needs to break through the bottleneck of gel ink: improving the dispersion stability of carbon black paste,optimizing the rheological and stability performance of gel ink,analysing and elucidating of the rheological adjustment mechanism and the dispersion stabilization mechanism of gel ink,which aimed at missing the mechanism gap.The dispersion stability of the carbon black paste are directly affected theoverall performance of the gel ink.The influences of the hydrophilic hydrophobic equilibrium value(HLB)and the amount of surfactant on wettability,dispersivity and stability of carbon black in color paste were investigated.By means of equivalent wetting contact angle,wetting heat,constructing the dispersion function and stable function,setting up the ideal model and so on,the paste stability of the color paste were evaluated.In the meantime,the stability mechanism was analyzed.The results showed that whether added single or complex surfactant,the HLB value was close to the carbon black HLB that good wetting,dispersing and stabilizing effect can be achieved.The dispersion stability of using complex surfactant was better than using single surfactant.In addition,adding anionic and nonionic surfactants had a better dispersion than adding non-ionic and nonionic surfactant.When the amount of surfactant achieved to 5.0wt%,the dispersion stability of the system was the best.The theories of adsorption layer and binding force can explain the phenomenon of the best addition and the best HLB value preferably.The rheological adjustment of gel ink mainly depends on adding functional additives,appropriate rheological parameters are of great significance for improving the writing performance of gel ink.The relationship between thickener,carbon black,surfactants of different HLB and the rheological property of gel ink was investigated,The rheological property of gel ink was characterized by means of rotary rheometer.The results showed that the viscosity,thixotropy and yield stress of gel ink were increased with the addingquantity of thickener or carbon black,It was not conducive to regulate the rheology of ink,when adding thickener content was too high or too low,When adding the single thickener TT-615 or TT-935,It was difficult in getting the right thixotropy,Complex thickener was conducive to adjust the appropriate thixotropy of gel ink;In addition,the viscosity,thixotropy and yield stress of gel ink were increased with adding the quantity of carbon black,thickening effect of the thickener was enhanced by addition of carbon black,The viscosity,thixotropy and yield stress of gel ink were decreased with adding the quantity of surfactant,because it would compete with the thickener adsorption and destruct the network structure,In the condition of thickener TT-615 0.8%(mass fraction),TT-935 0.6%,carbon black 7.5%,surfactant OP-10(HLB=14.5)1.5%,the rheology and coloring of gel ink can match with You&I ink of Korea.Grasping the law of rheological regulation of gel ink by surfactant plays a significant role in optimizing rheological data.For gel ink,making a comparison with the ability to adjust the rheological parameters and stability by adding the surfactants(single or complex)with different HLB values were studied.The results showed that when HLB values of system were the same during using single or complex surfactant,their rheology adjustment capacity were similar,The rheology adjustment capacity of the surfactant weakened with the HLB values raised,The gel ink stability of using complex surfactant was better than using single surfactant,Besides,adding anionic and nonionic surfactants had a better stability than adding non-ionic and nonionic surfactant;The effect of thesurfactant HLB value on the stability of the gel ink were in good agreement with the effect on the stability of the carbon black paste.When the amount of thickening agent and carbon black was constant,Suitable rheological properties and high stability can be achieved with adding surfactant A-X(HLB=14.5)1.5%.Temperature and pH are important factors that affect the rheological and stability properties of gel inks.The effects of temperature and p H on the viscosity,yield stress,thixotropic index,consistency coefficient,and flow index,Stability,temperature resistance of gel ink were studied.The results showed that changing the temperature could not change the characteristics of pseudoplastic fluids of gel ink;under the condition of the same shear rate,as the temperature increased,the apparent viscosity and shear stress would decrease accordingly;The relationship between temperature and consistency coefficient of gel ink,can be fitted with the Arrhenius equation model K=Aexp(Ea/RT);The relationship between temperature and flow index,can be fitted with a quadratic polynomial model;the low temperature was beneficial to the stability of gel ink,the temperature resistance of self-made gel ink was between You&I ink of Korean and commercial ink;The pH had a slightly effect on the apparent viscosity of gel ink,the apparent viscosity of the gel ink at pH 8-9 was relatively high,but the regularity of impacting on other rheological data was not strong;When the pH was too low or too high,it was not conducive to the stability of gel ink;at pH 8-9,a relatively better stability could be achieved.This article correlated the HLB value of surfactant and the HLB value of carbon black,the stability of pastes added with single or mixed surfactant was investigated to determine the best HLB value and amount of surfactant;Simultaneously,The effect of the interaction between thickeners,surfactant,and carbon black on rheology was studied,the optimal addition and compounding method of three additives have been determined;Then the rheological adjustment ability of surfactants(single or complex)with different HLB values and the effect on gel ink stability were studied,and determined the best compounding method of surfactant;Finally,the effects of temperature and pH value on the rheological properties of gel ink were studied,the weather resistance and durability of ink have been improved.The study found in this paper laid a good foundation of practice and theory for preparing high-quality domestic gel ink,it was conducive to advance the process of realizing a strong pen making country.