INK BACKFLOW PREVENTIVE FOR WATER-BASE BALL PEN

摘要

The ink backflow preventive of the present invention contains at least refractory and/or involatile organic liquid substances and gelling agents, wherein the oil separation degree under the specific condition is prepared to be 1 to 15 %, in which as at least said gelling agents, styrene-based thermoplastic elastomer is contained and said styrene-based thermoplastic elastomer is composed of two or more of said styrene-based thermoplastic elastomer with the same molecular weight and with the different average molecular weight.