| 摘要 |
PURPOSE:To obtain the title composition having excellent capability of preventing the corrosion in the adhesion area between a polyurethane primer and steel, by mixing a specified isocyanato-terminated urethane prepolymer and an inorganic filler. CONSTITUTION:A polyether polyol and/or a polyolefin polyol having a molecular weight of 200-1,500 and 2-3 hydroxyl groups in the molecule is reacted with an organic polyisocyanate compound having 2 or more isocyanato groups (e.g., diphenylmethane diisocyanate) at a ratio of NCO to OH of 1.6-3.0, thereby giving an isocyanato-terminated urethane prepolymer (A) having an isocyanato group content of 5-15%. 100pts.wt. component A, after adjusting the viscosity at 25 deg.C to 1,000cP or lower by adding thereto a solvent having a solubility parameter of 8.5-11, on reactive with an isocyanato group, is mixed with 20-300pts.wt. inorganic filler (e.g., SiO2) having an average particle diameter of 10mum or smaller.
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