Study On The Effect Of Auxiliaries On The Properties Of Pigment Purple Gel Ink

China is worthy of the name of the pen making power,80 percent of the world's pens from China,among which,the gel pen accounted for the most.With the development of pen making industry over the years,the independent research and development of gel ink,the core technology of pen making,has also made remarkable progress.However,advanced ink is still dependent on imports,especially in the field of color gel ink,which restricts China from a big pen maker to a powerful pen maker.Therefore,it is of great significance to promote the independent research and development and technical innovation of color gel ink for the high-quality development of pen making industry in China.At present,the main reasons hindering the development of color gel inks in China are as follows:(1)it is difficult for organic pigments with large specific surface area to disperse in aqueous solution;(2)a single thickening system is difficult to meet the rheological properties of color gel ink;(3)the writing lubrication of color gel pen needs to be improved.At present,most of the colored gel inks reported use resin as dispersant,and there are few reports on the rheological properties and lubrication properties of colored gel inks.Based on this,the idea of using super-dispersant to disperse pigment Purple 23 in water to improve the dispersion stability of organic pigment in water,and combining different kinds of thickeners and lubricants to realize the development of high quality purple gel ink is proposed in this paper.This paper first explored the influence of three kinds of super-dispersants on the pigment purple 23 dispersion system,and a resin dispersant as a contrast,to investigate the type of dispersant and the amount of added on the color paste D₉₀ particle size,centrifugal stability.The effects of grinding time,face to base ratio,particle size distribution,D₉₀ particle size,stability of the color paste were studied.The micro-dispersion state of the ink was observed by TEM,and the mechanism of dispersant on pigment purple 23 was analyzed by FTIR.Secondly,the effects of single and compound DR-72 and xanthan gum on rheological data,thixotropic value and thixotropic loop area of gel ink were investigated,and the effects of rheological properties on writing performance were investigated.Finally,the effects of single and compound polyols and surfactants on the friction coefficient,surface tension,viscosity and other parameters of gel ink were investigated,and the wear of pen tip was observed through a microscope.Finally,high quality purple gel ink was produced.The main research results are as follows:(1)The particle size of purple paste D₉₀ can reach 138 nm,and the centrifugation stability is 98%,and the thermal stability is the best,when 15 wt.%mass fraction of polyethylene oxide and polycyclic aromatic block copolymer dispersant is added at 2500r/min,the filling rate is 80%,and the grinding time is 2 h.The driving force of the adsorption between the dispersant and pigment violet 23 is that the hydrophobic group of the dispersant(viscous cyclic aromatic hydrocarbon)and the benzene ring structure of pigment violet 23adsorb through?-?accumulation,which causes the change of the infrared absorption of C-H bond.(2)The viscosity of single xanthan gum thickening system does not change with the addition amount at medium and high shear rates,and always keeps at 100±10 m Pa·s and 30±5m Pa·s.The addition of DR-72 to xanthan gum system can increase the viscosity of the system at medium and high shear rates.(3)When the addition amount of xanthan gum and DR-72 were 0.6 wt.%and 1.2 wt.%respectively,the optimal mixture ratio was reached.At this time,the viscosity of gel ink under low shear force was 1300.4 m Pa·s,the thixotropic value was 4.33,and the area of thixotropic return loop was 91.33 Pa/s,which met the industry standard.The ink line ink drop,ink output in the first 200 m,length,water resistance are good.(4)When the mixture of glycerol and PEG-200 is 1:1,the friction coefficient is the best to reduce,and the friction coefficient is 0.277.(5)Oleic acid and fatty alcohol polyoxyethylene ether phosphate were added 0.5 wt.%and 1.0 wt.%,respectively,to achieve the best composite effect,the friction coefficient was0.164,when the tip of the pen only slight wear.The effects of three additives on the properties of purple gel ink were investigated,and the system of purple gel ink was optimized.The prepared purple gel ink was comparable to foreign advanced inks,which provided a reference for the research and preparation of color gel ink.