Synthesis And Characterization Of UV Cured Polyurethane Dispersions Based On Sulfonate

The characteristics of Ultraviolet (UV) curing technology are energy saving,high-efficiency, excellent coating performance and suitable for thermal substrates, etc.Compared with oil UV curing system, water-borne UV curing system is environment friendly,nontoxic, and easier to construction. It could be used as coatings based on metal, wood,plastic, glass, etc. UV-curable polyurethane dispersions (UV-PUDs) has the best combinationproperty in the water-borne UV curing system. At present, hydroxycarboxylic acids areusually used to synthetize UV-PUDs, but to synthetize UV-PUDs needs high dosagehydroxycarboxylic acids and the hydrolysis resistance is not very good. Using single hydroxylacrylic ester to synthetize UV-PUDs is the most used mothod, but the content ofcarbon-carbon double bond in UV-PUDs and the crosslinking density of films that are afterUV cured is low, is low, so that the coating performance is poor. Researches show that usingdihydric acrylic ester to synthetize UV-PUDs and modified by nano materials, epoxy resincould improve the content of double bond and film property. However, these methodsremained at the stage of laboratory.UV cured polyurethane dispersions（UV-PUDs）and epoxy acrylate modified UV-PUDswere synthesized by using polyether diol containing sulfonate(SPPG), isophoronediisocyanate(IPDI), polycarbonate diol(PCDL-1000), pentaerythritol triacrylate(PETA),epoxy acrylate(EA). And Water-borne UV-curable wood coatings were prepared with coatingadditive and photoinitiator. The hydrophilic group content, R value[R=n(-NCO)/n(-OH)] andthe EA content effect on the properties of UV-PUDs and UV-curable wood coatings wereresearched.The properties of UV-PUDs were measured by Brookfield viscosity, Laser particle sizeanalyzer and TEM analysis. The three variables effect on the viscosity, average particle size,particle size distribution and the morphology of UV-PUDs were researched. The properties ofUV-PUDs films were surveyed by infrared spectroscopy（FT-IR）, water absorption, gelcontent, thermogravimetric analysis（TGA）, differential scanning calorimetry（DSC）,etc. Thethree variables effect on the water absorption, UV curing efficiency, thermostability, glasstransition temperatures(Tg) were researched. The properties of UV-curable wood coatings were surveyed by the test of glossiness, pencil hardness, adhesion, blocking resistance, heatresistance and chemical resistance including water resistance, ethanol resistance, alkaliresistance, acid resistance, stain resistance. The three variables effect on the properties ofUV-curable wood coatings were researched. The UV-PUDs were stabilized and had highperformance. The properties of UV-curable wood coatings were improved by adding epoxyacrylate. The glossiness and pencil hardness of coatings were up to94and2H and show ahigh application value.