| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an ink composition which does not deteriorate rubber or resin stamps and is easily removable from a surface to which it is attached, by incorporating polyoxyethylene-oxypropylene triol, a colorant, an acrylic resin, and a body pigment into the same. SOLUTION: This ink composition contains 50-90 wt.% polyoxyethylene- oxypropylene triol represented by the formula, 1-30 wt.% colorant (e.g. a pigment or an oil-soluble dye), 0.1-30 wt.% sum of an acrylic resin having a glass transition point of 80 deg.C or lower and a body pigment (e.g. precipitated barium sulfate), a penetration aid, an antiseptic and antimildew agent, an antioxidant, etc., and is adjusted so as to have a viscosity of 500-3,500 mPa.s at 25 deg.C and 20 rpm, a viscosity of 300-3,000 mPa.s at 25 deg.C and 100 rpm, and a ratio of viscosity at 20 rpm to that at 100 rpm, both at 25 deg.C, of 1.0-1.2. The polyoxyethylene-oxypropylene triol is formed by the etherification of three hydroxyl groups of glycerin with an ethylene oxide-propylene oxide block copolymer and preferably has a number average mol.wt. of 200-6,200.</p> |
