| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an ink composition which itself is not hygroscopic and is not driable, does not deteriorate a stamp made from a natural rubber or the like, is amenable to the removal of the ink adhering to the surface of a stamp, and is ready for ink supply by incorporating a specified polyoxyethylene propylene triol with a colorant and a specified vinyl acetal resin. SOLUTION: This composition comprises 50-95 wt.% especially, 60-80 wt.% polyoxyethylene oxypropylene triol represented by formula I, having an average molecular weight of 200-6,200, and obtained by ether-bonding of a block copolymer of ethylene oxide with propylene oxide to the three functional groups of glycerol, 1-30 wt.%, colorant selected among organic and inorganic pigments and 0. 1-10 wt.% polyvinyl acetal resin comprising 0-3 mol.% polyvinyl acetate, 55-70 mol.% polyvinyl acetal, and 25-45 mol.% polyvinyl alcohol, having a decree of polymerization of 100-300, and represented by formula II (wherein R is H, CH3, CH2CH3, CH2CH2CH3, or formula III).</p> |
