Study On Colorlessness And Stabilization Of Rosin Esters

The high stable colorless rosin esters were prepared from rosin and polyhydric alcohol. The application of chemical additives including catalysts, antioxidants, and light stabilizers in rosin and rosin esters were studied firstly systematically.Antioxidant PS-10 with good decoloring effect to rosin and its reaction conditions were studied. The results showed that amount of PS-10, reaction temperature and reaction time were main affecting factors, especially the reaction temperature. The optimal technology was got by the mathematical model-"Quadratic Orthogonal Rotable Combination Design" as follows: PS-10 0.175%, reaction temperature 272℃ and reaction time 4hr. The colorless rosin glyceride, color 125 (Hazen), acid value less than 10.0mg/g, and softening point more than 85.0℃, was prepared by using the colorless rosin and traditional esterification method.The affecting factors of quality of colorless rosin pentaerythritol ester including color of material rosin, kinds and amount of catalysts, amount of PS-10 and pentaerythritol, reaction temperature and reaction time were studied. The optimal technology were determined by orthogonal experiment as follows: amount of catalyst C-14 0.3%, antioxidant PS-10 0.2%, and pentaerythritol 11.8%, reaction temperature 270℃, and reaction time 6hr. The quality indexes of rosin pentaerythritol ester were color 125(hazen), acid value 19.7mg/g, and softening point 103.5℃. The color of material rosin was the one of key factors of affecting color of rosin esters.The kind and amount of antioxidants and light stabilizers were studied. The results showed that high stable rosin pentaerythritol ester could been got when antioxidant B900 0.3% and light stabilizer LD622+UV320 0.4% were added in colorless pentaerythriol ester. Its color was less than l(gardaner) when heated 8hr at 180℃; increment in weight 0.21% and color 3-4 (gardner) when irradiated 15hr under 400W ultraviolet lamp; its stability was also much better than that of blank at 40 ℃.The high stable colorless rosin pentaerythritol ester was produced industrially, the quality of products was close to that of laboratory products and also reach the standards of Arakawa's same kind products.