制备了二聚体含量为23.5%~90%的聚合松香,用于酚醛树脂的改性。研究了聚合松香中二聚体含量、酚醛浆及顺酐用量等因素对制备改性酚醛树脂的影响,揭示了这些因素对树脂产品的软化点、黏度及正庚烷值等指标的影响规律。当酚醛浆用量为聚合松香的25%,聚合松香的二聚体含量为50%~65%,顺酐用量为聚合松香的2%~3%时,得到了黏度为6000 mPa.s/35℃~20000 mPa.s/35℃,软化点为180℃~190℃,正庚烷值为8 mL/3 g~12 mL/3 g的聚合松香改性酚醛树脂产品,可用于高档胶印油墨的生产。
Polymerized rosin with dimer contents of 23. 5%~ 90% was synthesized for the modification of phenolic resin. The effects of dimers content of polymerized rosin, dosage of resol and maleic anhydride On the synthesis of modified phenolic resin were studied. The results show that these factors affect the softening point, viscosity and n-heptane value of the resulting resin in a regular way. A resin with viscosity 6000 mPa.s/35℃~20000 mPa.s/35 ℃, softening point 180 ℃~190 ℃, n-heptane value 8 mL/3 g~12 mL/3 g was synthesized when a dosage of 25% of phenolic resin gel was used to react with polymerized rosin containing 50%,~65% dimers and 2% ~3~ maleic anhydride, this kind of modified phenolic resin is suitable for the manufacture of high quality offset printing ink.