Synthesis Of Acidic Ionic Liquids And Their Catalytic Property For Rosin Esterification

Rosin is a very important industrial forest products and chemical forest products. Esterification is one of the most basic means for rosin modification. At present, account for above 60% in all kinds of rosin modified products is rosin esterified products, which is widely used in paint,printing ink,adhesive,furniture,rubber and so on. Ionic liquid is a new kind of environmental-benign material with excellent solubility, high boiling point,good thermal stablility and adjustable acidity.In this paper, several kinds of imidazolium ionic liquids([Emim][PTSA] and so on) catalyst were synthesized and characterized. Polyol ester were prepared through the esterification of gum rosin with polyol(pentaerythritol,glycerol,glycol). The effects of reaction conditions on esterification reaction were also studied. SBS hot melt pressure-sensitive adhesive was prepared using polyol ester of rosin as tackifying resin. Its mechanical properties were tested, and the dynamic viscoelastic properties were studied by rheometer. The major work and conclusions have shown the following:1. Imidazolium ionic liquids including [Emim][HSO4],[HSO3-(CH2)4-mim][HSO4],[Bmim][HSO4],[Omim][HSO4],[Emim][PTSA] and[HSO3-(CH2)4-mim][H2PO4] were synthesized by two-steps method. The products were characterized by FT-IR and NMR.2. Pentaerythritol ester was prepared through the esterification of gum rosin with pentaerythritol using ionic liquids as catalysts. The effects of reaction conditions on reaction results were studied. As shown by the results, all synthesized ionic liquids exhibit different catalytic activity to the esterification of gum rosin with pentaerythritol. [Omim][HS04] ionic liquid shown the best catalytic activity. The optimized reaction conditions were:n.OH:n_COOH=1:1, reaction temperature of 260℃, reaction time of 8h and dosage of the ionic liquid of 0.05%(based on rosin weight). In this case, the obtained products had an acid number of 24.6mgKOH/g, a softening point of 98.5℃, a color number of 4+(Fe-Co method), and a yield of 99.4%. Compared with the products prepared with traditional catalyst ZnO, this kind of products had better performance.3. Glycerol ester was prepared through the esterification of gum rosin with glycerol using ionic liquids as catalyst. The effects of reaction conditions on reaction results were studied. As shown by the results, all synthesized ionic liquids exhibit different catalytic activity to the esterification of gum rosin with glycerol. [HSO3-(CH2)4-mim][HSO4] ionic liquid shown the best catalytic activity. Under the optimum reaction conditions of n.OH:n_COOH=1.1:1, reaction temperature 260℃, reaction time 7h and dosage of the ionic liquid 0.03%(based on rosin weight), the obtained product had an acid number of 9.6mgKOH/g, a softening point of 90℃, a color number of 4 (Fe-Co method), and a yield of 100.2%. Compared with the products prepared by using traditional catalyst ZnO, this kind of products had better performances.4. Glycol ester was prepared through the esterification of gum rosin with glycol using ionic liquids as catalyst. The effects of reaction conditions on reaction results were studied. As shown by the results, all synthesized ionic liquids exhibit different catalytic activity to the esterification of gum rosin with glycol. [HSO3-(CH2)4-mim][HSO4] ionic liquid shown the best catalytic activity. Under the optimum reaction conditions of n_OH:n-COOH=1.1:1, reaction temperature 270℃, reaction time 6h and dosage of the ionic liquid 0.03%(based on rosin weight), the obtained product had an acid number of 10.3mgKOH/g, a softening point of 56℃, a color number of 4 (Fe-Co method), and a yield of 99.4%. While traditional catalyst ZnO hardly promoted the esterification of gum rosin with glycol.5. SBS hot melt pressure-sensitive adhesive was prepared using polyol ester of rosin as tackifying resin. Its mechanical properties were tested, and the rheology behaviors were studied by dynamic-viscoelastic frequency-scanning technique in the range of adhesion frequency(0.01Hz) to peeling frequency(100Hz). The results indicated that low polymer storage modulus leads to great initial adhesion under the adhesive frequency (0.01Hz), and polymer with great values of loss modulus have great 180°peel strength under the peeling frequency(100Hz), and those with great values of rη, G'give long sustained adhesion time under the low frequency(0.01～1Hz).