Macromolecular diols common macromolecular and polyether diols include poly cool, Mn500 12,000, flexibility good for finishing agent of polyether should be adopted, it is because ether based cohesive energy than cool base within shaped (12)/Inol). Diisocyanate unitary purpose all the finishing agent for light resistance requirements are very high, 1.6-cool six methylene diisocyanate (HDI), belonging to the aliphatic isocyanate cool, stable to light, made of polymer is not easy to turn yellow. Chain Extender in polymerization, owner chain adjustment prepolymer ratio of hard and soft chain, you can change multiple alcohol and macromolecules diisocyanate feeding weight, or join the more than two faculties or two faculties of polyols chain Extender, the reaction with n-methyl diethanol amine as chain Extender. Catalysts to speed up the polymerization speeds, dibutyltin February GUI acid commonly used catalysts, bitter stannous. Solvent in order to ensure in the reaction process of polymer a certain degree of liquidity, to add to that with which the polymer is dissolved and does not participate in the reaction solvent dilution, usually using benzene, toluene, acetone, methyl ethyl ketone, cyclohexanone, etc.