| 摘要 |
<p>An abrasive product contains particles of an abrasive material, animal hairs and/or synthetic or natural fibres, and a binder which is essentially the reaction product of a polyether and an isocyanate. Preparation is in a mould having holes of diameter 0.5 - 1 mm. These allow the escape of gas produced in the condensation reaction but prevent the escape of solid matter. Uniform products having a very even distribution of the abrasive are produced. Uses are for the finishing of wood, leather, rubber, plastics and metals. The binder is prepared from a propylene oxide based polyether having terminal hydroxyl groups, toluene diisocyanate or diphenylmethane diisocyanate, triethylamine, urea, stannic octoate and a silicone oil. Moulding is at 70 deg.C for 25 minutes; postcure is at 130 deg.-150 deg.C for about 1 hour.</p> |
