| Summary: | 碩士 === 國立屏東科技大學 === 木材科學與設計系所 === 95 === The formulations of coating colors for inkjet printing paper comprise mainly silica, polyvinyl alcohol and cationic additives. Because of the high porosity, hydrophilicity and specific surface area of silica, water- based printing inks could quickly be absorbed, resulting in the mitigation of drying time for printing inks, and consequently the improvement of color sharpness and edge clearness of the text and figures. The solid content of the coating colors couldn’t be raised due to silica’s high water absorbancy, so does the coating speed, let alone an extra need of drying energy at the later stage of coating. The objectives of this study are to examine the feasibility of partially replacing silica with three types of precipitated calcium carbonates (PCC), and to investigate its effect on the properties of coating colors and the optical properties and printability of the paper thus produced.
The highest solid content of the PCC-free coating colors was recorded 15 ％. When the replaced amount was 10 and 15 ％,the coating color solid content could be increased up to 17 and 19 ％, respectively. The coating colors’ viscosity showed that partially replaced by three types of PCC decreased with increasing replacements. At the same replaced amount, the higher specific surface area of PCC, the higher viscosity of coating color they are.
For the optical properties of paper , coating color increasing the solid content of coating color could be helpful for paper’s brightness, opacity and gloss. The addition of three types of PCC to silica would result in better optical properties of paper than that of silica alone. When coating color solid content was 19 ％ and the PCC substitution amount was 20 ％, the paper’s brightness, opacity and gloss would increase 0.3, 1.1 and 8.8 ％,for PCC (C-1)；0.8, 1.5 and 8.8 ％ for PCC (C-2), and 2.2, 2.3 and 9.6 ％ for PCC (C-3),respectively. There are no significant difference between C-1 and C-2 for paper’s gloss properties. However, the C-3 showed better than those of C-1 and C-2 and control for optical qualities of paper.
For paper printability, when coating color solid content was 15 ％ and only used silica, the paper’s color densities of four color (Cyan, Magenta, Yellow, Black) showed better than those other two solid contents with partial PCC replacement. When the replaced amount was fixed, the four-color density values were the highest for C-1, and C-3 was the lowest. The replaced amount must be up to 20 ％,the four color differences were just above 3, for C-1 and C-2 when coating color solid content was 15 ％,but the four color differences would be just above 3,for C-3 when the replaced amount was 15 ％. When coating color solid content up to 19 ％,the four color densities and color differences would be improved for C-1 and C-2 when their replaced amount were 20 ％,but C-3 was only at 15 ％ replacement.
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