Synthesis Of Polyurethane Acrylate And Development Of The Ultraviolet Curing Leather Coating

Ultraviolet(UV) cured coatings have made large growth and extensive application because of their excellent performance and green environmental protection . This paper studies the process conditions on synthesis of polyurethane acrylate(PUA) resin and the factors which influence the viscosity of PUA resin through synthesis of polyurethane acrylate and application on the ultraviolet cured leather coating. We attain a kind of ultraviolet cured leather coating with excellent performance finally through trial of formulation and optimizing process. The appraisal of the UV leather coating were gained in charge of office of scientific and technological of Hunan Province. The experts thought that the product filled in blank of the domestic relevant application, belonged to domestic initiation and the technology had reached the international advanced level.This paper studies the synthesis of a series of PUA resin with two functional group by selecting the different polyols kinds and the different molecular weight polyols. The process conditions on synthesis of PUA are researched from all aspects by the experiment, such as the route, catalyst, reinforced way, response temperature, etc. We discuss the factor which influenced the viscosity of the PUA resin from molecular structure and process conditions. The best process conditions of the synthesis of PUA is summarized : First, polyols and TDI react and turn into the prepolymer with NCO group under 50- 60 Centigrade of temperature; Second, the reaction will be ended at 60-70 Centigrade, adding HEA at a certain speed, while the catalyst is ditin n-butyl dilaurate which use 0.05% of the whole quantity (while the reaction temperature of IPDI is 10 Centigrade lower than the temperature of TDI). PUA resin is the best in storing stability and speed on UV reaction while the mol rate of polyol: TDI: HEA is 1:2. 05:2.15. The influential factors on the viscosity of PUA resin are discussed from molecular structure and process conditions. The important factor influencing on the viscosity is degree of polymerization while PUA resin molecule designed, the viscosity of resin increases notably with the polymerization degree of molecule increasing. When the degree of polymerization of resin is same, the molecular weight of intermedia influence on the viscosity of PUA. Generally, the viscosity of PUA resin is lower while the molecular weight of the polyols is higher. But the viscosity of PUA resin of PTMG is higher while the molecular weight of the polyols is bigger. In addition, the route ofsynthesis and reinforced way will influence the viscosity of PUA resin.The polyols determine the main performance of PUA resin. The curing rate of PUA composed of the same type polyols is lower while the molecular weight of the polyols is bigger. Comparing different kinds of PUA , polyether type PUA cure faster than polyester. The rate of PUA which was synthesized by PPG is lowest among the polyether type PUA resins. We find that the polyurethane acrylate resin with hydroxyl terminated polybutadiene(HTPB) or polytetramethylene glycol(PTMG) as skeleton have good flexibility and excellent low-temperature zigzag resistance through the application of UV cured leather coating. And the polyurethane acrylate which is modified by HTPB has extremely elasticity excellent adhesive and fast speed, however, it is only suitable for the manufacture of high viscosity UV cured coatings because of large viscosity and bad dissolved ability. Based on the polyurethane acrylate modified by PTMG, the performance of ultraviolet cured leather coating is researched from a lot of respects, such as mononer, photointiator, co-initiator,addition and process conditions etc, a kind of UV cured leather coating with high performance is manufactured finally.