Patent ID: 7776941

Claim:
An oil-based ink composition for writing instruments comprising colorant(s), resin(s), organic solvent(s), and gelling agent(s), wherein said organic solvent (s) is (are) hydrocarbons solvent (s), and in particular, at least one species of the solvent selected from the group of an aliphatic hydrocarbons solvent (s), alicyclic hydrocarbons solvent (s), aromatic hydrocarbons solvent (s), and halogenated hydrocarbons solvent(s), said gelling agent(s) comprises (comprise) soluble gelling agent (s) soluble to the above organic solvent (s) and insoluble gelling agent(s) insoluble to the above organic solvent, and the above insoluble gelling agent is an urea-modified thixotropic agent.