| 摘要 |
PURPOSE:To eliminate the possible creation of foams in the interface between the transparent urethane layer and the upper face of belt-shaped base by applying and drying urethane catalyst on the upper face of belt-shaped base material of synthetic resin, on which the polyurethane material consisting of the contents such as polyol and polyisocyanate are charged and cured to form a transparent polyurethane layer. CONSTITUTION:The base 1 is made of synthetic resin materials of high heat resistance and of high-impact properties such as polyvinyl chloride and the like, and is formed by extrusion or injection. Normal catalysts of amine family or organotin family to accelerate the urethane reaction is diluted with the solvents such as propyle alcohol and the like are applied. The transparent polyurethane layer 2 is formed with the polyurethane material consisting of sufficiently vacuum defoamed polyol and polyisocyanate being potted over the upper face 1a of the base 1. During the said process, the catalysts of heavy metals series or amine series normally used for polyurethane curing are added to the said polyurethane material. Heat curing is carried out for 10-30min at the temperature of 60-100 deg.C. |
