WRITING INSTRUMENT REFILL AND WRITING INSTRUMENT WITH THE SAME ATTACHED THERETO

摘要

PROBLEM TO BE SOLVED: To provide: a writing instrument refill causing no ink leakage due to ink backflow and having satisfactory ink followability; and a writing instrument with the writing instrument refill attached thereto.SOLUTION: A writing instrument refill 1 has a writing body attached to a front end of an ink accommodating cylinder 2. A writing instrument ink 5 is directly loaded into the ink accommodating cylinder, and an ink backflow preventing plug 6 is disposed separately from the ink at the rear of the ink. The ink accommodating cylinder accommodates therein a writing instrument ink composition composed of at least a coloring agent, an organic solvent, and a resin. The ink backflow preventing plug is a fiber bundle body not subjected to surfactant processing. Ink viscosity at 20°C and a shear rate of 5 secis 50000 mPa s or less.