100 parts of tall oil rosin acid value 167 was molten by heating at 210 u00b0 c and 10 parts of triethanolamine was added drop by drop over a period of 20 minutes cooh oh 1 0 68 while continuing dehydration at constant temperature a reaction was carried out for 5 hours the resulting resin had an acid value of 63 100 parts of tall oil rosin acid value 167 was molten by heating at 210 u00b0 c and 17 6 parts of maleic anhydride was charged in separate additions over a period of 1 hour and this temperature was kept for 2 hours the resulting resin had an acid value of 226 100 parts of tall oil rosin acid value 167 was molten by heating at 210 u00b0 c and 9 4 parts of maleic anhydride was charged in separate additions over a period of 20 minutes followed by a reaction at this temperature for 1 hour then 6 parts of triethanolamine was added drop by drop over a period of 20 minutes the mixture was heated to 230 u00b0 c and kept at this temperature for 3 hours the resulting resin had an acid value of 148 100 parts of tall oil rosin acid value 167 was molten by heating at 250 u00b0 c and 8 parts of glycerol was added drop by drop over a period of 20 minutes while continuing dehydration at a constant temperature a reaction was carried out for 10 hours then the temperature was decreased to 210 u00b0 c and 9 parts of maleic anhydride was carefully added gradually after the completion of the addition of maleic anhydride the mixture was kept at a constant temperature for 90 minutes the resulting resin had an acid value of 78 4 100 parts.