| 摘要 |
PURPOSE:To provide a cross-linker which improves the heat resistance of an acrylic rubber obtd. by the copolymn. with a monomer based on cyanoacetic or malonic acid. CONSTITUTION:Formaldehyde or its polymer is reacted with urea or thiourea in the presence of an acidic catalyst to give a cross-linker, which is used for cross-linking an acrylic rubber to give a cross-linked rubber excellent in resistance to heat, oil, and water. |
