Synthesis And Properties Of Waterborne Rosin-based Polyurethane And Their Two-component Film

Waterborne polyurethane has two merits:the high performance of solvent based polyurethane and the low VOC value of water based polyurethane(WPU).With the environmental protection consciousness gradually being strengthened and relevant regulations issued.the research of waterborne polyurethane has gotten more and more attention. This paper aimed at synthesizing one environmental friendly PU coating with high performance and renewable resources contained, and factors which affected the synthesis are also discussed.Through crosslinking with curing agent of polyisocyanates, studied effect of the factors on the process of forming a film, optimised the curing process conditions and discussed the influence of the performance of the film.In this paper the maleopimaric acid polyester polyols(MAPP) was synthesized from diglycol and maleric rosin which was the adduct of rosin and maleric acid by esterification. The product is white and the molecular weight is2.2×103by the determination of GPC.The structure was been characterized by FT-IR and1H-NMR and tested particle size and stability of the dispersion. Anion and cation two-component water-borne polyurethane coating containing hydroxyl components, namely polyurethane dispersion was prepared with homemade MAPP. Then two-component waterborne polyurethane based on rosin was prepared by combined hydrophilically-modified polyisocyanate with polyurethane dispersion. Infrared spectroscopy(IR) was used to characterize the curing film. The results showed the accordance with molecular structure. The effect of curing process on film performances was studied in detail. And the physical properties of the film, such as hardness, impact strength, flexibility, adhesion, water resistant and acid and alkali resistance were investigated systematically.Performances of films processinged by different polyols、isocyanate and content of MAPP was discussed through thermogravimetric analysis、tensile test and dynamic water contact angle. The experiment shows that with the increase of the content of MAPP, heat resistance, tensile strength, hardness have been improved significantly. The film with excellent performance was obtained:Its pencil hardness was6H, and the flexibility was0.5mm,10%thermo-gravimetric as high as309℃,tensile strength was20.1MPa. It achieved the performance standards of two-component solvent polyurethane coatings and greatly reduced the emissions of volatile organic and met the requirements of environmental protection.It would have broad application prospects in the field of coating and adhesive.