| 摘要 |
Novel, improved ink compositions are aqueous-based, shock-resistant, shearthinning inks for writing instruments having a shear index greater than 0.6. The inks are a substantially uniform dispersion including colorant(s), a water dispersible, polymeric shear-thinning material selected from the group consisting of welan gumrhamsan gum and combinations thereof, and a substantially water-soluble polymeric viscosity modifier in a polar solvent system. While the ink compositions have a high viscosity at low shear rates, they undergo shear-thinning and are readily flowable in response to shear rates produced in writing to provide a writing ink having an especially desirable combination of performance characteristics.
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