Study On Synthesis Of Light Colored Rosin Modified Phenolic Resin

The rosin modified phenolic resin, a mainly important one among all resins used as bands for offset inks, has the call for printing ink. With the development of industry which is demainding the high-qulity for product more and more, light colored rosin modified phenolic resin will become the only one which would have the better application prospect and competition in the international market than other.The esterification reaction in the presence of several catalysts , lightening agents, antioxidants for the synthesis of rosin modified phenolic resin was carried out in the research. The correlative reaction mechanism and the principle of the change of the resins properties were studied. The preferred synthetic process of light colored rosin modified phenolic resin was developed.In this thesis the content of free phenol in the rosin modified phenolic resins were determined by UV spectrophotometry. Meanwhile, the relationship between the content of free phenol and the color of the obtained resin was studied. It was shown that when the content of free phenol in the final resin was higher, the color of the obtained resin was deeper. The structure similar to quinone was discovered in the rosin modified phenolic resin, moreover, when the content of this structure was higher, the color of the obtained resin was deeper. The overall analysis of the above was shown that the presence of the structure similar to quinone which was resulted from the oxidation of free phenol in the obtained resin was the main cause for the deeper color of the rosin modified phenolic resin.In the presence of different kinds of catalysts , lightening agents, antioxidants, the esterification reaction course of rosin modified phenolic resin was also researched. It was shown that the substances belonging to phosphonate behaved the highest esterification catalytic efficiency among all the single catalysts system, but its catalytic efficiency was not good enough for the demand of shortening esterification time. Among the mutiply catalysts system, the phosphonate and AT215 or pentaerythrityl tetrakis [p-(3,5-di-tert-butyl-4-hydroxyphen)propionate] using together accelerate the esterification reaction obviously. The complex catalysts system SKW which was composed of salt of phosphonate, the phenol sulfide compound, a organic acid, showed the highest esterification catalytic efficiency among all. Moreover, the ratio of the three chemicals existed a optimum value which resulted in the highest cooperating esterification catalytic efficiency.Changes in the properties of the resin obtained by using different catalysts , lightening agents, antioxidants were also studied in the thesis. Results showed that the color of the resin in esterification reaction and the final products varied obviously with different catalysts, lightening agents, antioxidants. The resin with butyl stannonic acid as catalysts which showed lower esterification catalytic efficiency had relatively lighter color and better transparence than other single catalysts system, by comparison, substance A belonging to phosphonate used as catalysts could also improve the color of the obtained resin. The color of the obtained resin was decreased over 2 grades in the presence of phosphinic acid used as lightening agents in an amount of1.0 wt% based on the wight of rosin. The resin obtained by using the complex catalysts system SKW and phosphinic acid together had the lightest color among all. It was also found that the properties of the resin including n-heptane tolerance degree, softening point, viscosity varied obviously with different catalysts , lightening agents, antioxidants but they were all increased generally with time of temperature holding stage.In the research, by selecting new kind of catalysts system and adjusting ratio of raw materials in the temperature holding stage of esterification and changing operation process of synthesis of rosin modified phenolic resin, the color of the obtained resin is 3 grades lighter than that required by China enterprise's standard.