| 摘要 |
PURPOSE:To obtain an abrasive material without use of abrasive grains by making uneven the urethane surface of JIS C scale 85-99 deg. CONSTITUTION:62pts.wt. of polyisocyanate is allowed to react with 100pts.wt. of polyester of molecular weight of 2,000 at about 110 deg.C for 60min to synthesize polyurethane pre-polymer. 11pts. of 1, 4 butanediol being a crosslinker is further added to this to permit a further reaction at temperature of 120 deg.C for two minutes to be executed. Mirror polishing of the surface such as a lens, etc., is enabled even without abrasive grains for polishing by making uneven the surface of urethane forming a polyurethane sheet for an abrasive material of JIS C scale 90 deg. by injecting said reaction product into a forming die. |
