Chi (χ)-alumina dispersion and application to coating slurry of digital printing medium
AssigneeNational Cheng Kung University
InventorsFu-Su Yen, Tzung-Jiung Wu
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Abstract
A chi (χ)-alumina dispersion and coating slurry of digital printing medium containing the same is disclosed, which includes flaked porous χ-alumina nanoparticles with high specific surface area obtained by subjecting gibbsite to thermal treating, physical wet-milling and pH adjusting processes. Since the χ-alumina nanoparticles have high ink absorptivity and low cost, they can be applied to the coating layer of the digital printing medium instead of conventional silica material.
Claims10
A chi (x)-alumina dispersion characterized by subjecting gibbsite to thermal treating, physical wet-milling and/or mixing and pH adjusting processes, so as to obtain the x-alumina dispersion containing flaked porous x-alumina nanoparticles without gamma (y)-alumina, wherein the flaked porous x-alumina nanoparticles have a specific surface area of 100 m2/g to 220 m2/g, an average thickness of 10 nm to 200 nm, an average cross-sectional diameter of 20 nm to 1000 nm, pore size over a surface of the flaked porous x-alumina nanoparticles of 1 nm to 10 nm, a solid content of 20 wt. % to 40 wt. %, a pH value of 2 to 6, and a coating layer formed by the x-alumina dispersion without dyes and pigments has water resistance and an ink absorptivity of 1.5 mg/cm2 to 1.8 mg/cm2.
A coating slurry for digital printing, comprising:
- x-alumina dispersion, wherein the x-alumina dispersion comprises flaked porous x-alumina nanoparticles evenly dispersing in water or acidic solution without gamma (y)-alumina, and the flaked porous x-alumina nanoparticles are formed by subjecting gibbsite to thermal treating and physical wet-milling processes, and the flaked porous x-alumina nanoparticles have a specific surface area of 100 m2/g to 220 m2/g, an average thickness of 10 nm to 200 nm, an average cross-sectional diameter of 20 nm to 1000 nm, and pore size over a surface of the flaked porous x-alumina nanoparticles of 1 nm to 10 nm;
- and
- an adhesive added into the coating slurry in an amount of 8 wt. % to 20 wt. %, wherein the adhesive is selected from the group consisted of poly(vinyl alcohol) (PVA), casein, rosin glue and paraffin glue;
- wherein the coating slurry has a solid content of 20 wt. % to 40 wt. %, a pH value of 2 to 6, and a coating layer formed by the coating slurry without dyes and pigments has water resistance and an ink absorptivity of 1.5 mg/cm2 to 1.8 mg/cm2.
Dependencies are inferred from the claim text.