| With the rapid development of inkjet printing technology,its market share is continue growing.Ink-jet printing coating layer determines the print,inkjet printing coating layer can be divided into three kinds,light weight sizing layer,polymer coating layer and pigment coating layer,and the optical density,print resolution,ink drying speed and Color performance of the pigment coating layer is the best.However,the production cost of high-quality inkjet printing pigment coating layer is too high,which constraints on the large-scale application of pigment coating layer,mainly because the main raw material silica pigment price is too high,the amount of adhesive,coating color low solid content,low Coating speed and other reasons.So,there is an urgent need to develop a low cost,excellent print quality,the less required amount of adhesive,instead of silica as pigment in inkjet printing coating layer.In this paper,the feasibility of using starch as the pigment in the inkjet printing coating layer was studied.The starch type suitable for the inkjet printing coating was optimized.The starch granules were modified by chemical method to improve the print quality of the starch printing coating layer.The starch nanocrystal and starch nanoparticles were prepared by acid hydrolysis and regeneration respectively,and height quality inkjet printing coating layer was prepared with starch nanocrystal;Specific research are as follows:1.The feasibility of the application of starch as a pigment in inkjet printing coating was discussed.The properties of four kinds of starch(native pea starch,native cornstarch,native cassava starch and native rice starch)were investigated by SEM and print quality(Optical density,gamut area,printing resolution).The results showed that native corn,cassava and rice starch were used as the inkjet printing coating pigment in addition to pea starch,which was suitable for the inkjet printing coating.The results showed that the optical density of the rice starch coating layer was better than other starch coating layer about 24.93%,and the gamut area of the color area was increased by 26.84%,dot and line resolution compared with the base paper were increased by 39.15% and 33.17%.2.The effects of the chemical properties of starch on the print quality of the coating layer were studied.The results of SEM,FT-IR,XRD and DS showed that the physical properties of modified rice starch were modified was not changed.By comparing the print quality of\ the coating layer,it was found that the total optical density of the rice cationic starch coating layer was increased by 27.42%,the color gamut area increased by 39.26%,and the dot and line resolution were improved 33.35% and 19.83% respectively.At the same time compared with the addition of cationic fixing agent PDADMAC rice starch coating and rice cationic starch / PVA coating print quality,rice cationic starch coating printing optical density,color gamut area,dot and line resolution than adding PDADMAC cationic fixation coating layer increase 12.44%,12.67%,54.16% and 47.7% respectively.3.The interfacial relationship between the addition of inorganic pigments and the penetration of ink in the coatings layer was studied by adding the inorganic pigments commonly used in the native starch / PVA coating.The results of SEM and ink penetration showed that the addition of inorganic pigments in the starch/PVA coating can alter the structure of the coating layer and enhance the barrier properties of the coating to the ink,in which it is necessary to add kaolin(KL)equivalent to 10 parts of dry powder,20 parts of calcined kaolin(CKL),or 30 parts of ground calcium carbonate(GCC),or 40 parts of precipitated calcium carbonate(PCC);and then by comparing the print quality of the coating,the printing performance of adding 20 parts CKL and 40 parts PCC,30 copies GCC and no pigmented starch coating is basically the same,which added 10 copies of KL into the coating layer print quality significantly deteriorated,point and line resolution by 31.79% and 50.06%;overall performance CKL is the best,followed by PCC,GCC,KL.4.The effects of starch nanocrystaline(RSNCs)and starch nanoparticles(RSNPs)on the application of inkjet printing coatings were studied by acid hydrolysis and regeneration.FT-IR,XRD and SEM results show that RSNPs are easily soluble in water and cannot be used as a coating pigment.Starch nanocrystal can be used as pigments and adhesives at the same time.The print quality of RSNCs coating layer is excellent.The optical density,gamut area,dot and line resolution of the coating layer were improved by 54.75%,77.17%,47.87% and 33.01%,respectively.By contrasting RSNPs and PVA as adhesive in coating layer's Print quality,add 10 parts of RSNCs as an adhesive without ink penetration to the paper back,greatly enhanced the coating on the ink barrier capacity;and significantly improve the native rice starch coating layer properties of rice,which use RSNCs as adhesive coating the optical density,gamut area,dot and line resolution of the printing layer were 21.97%,21.14%,14.05% and 12.81% higher than those of PVA adhesive. |
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