brief history
19 19 German A.Grun and R.Winkler first proposed the polymerization method of rosin. With concentrated sulfuric acid as catalyst, rosin was dissolved in petroleum ether and treated at -5℃ for 6 hours to obtain rosin. Since 1930s, the production workshop of polymerized rosin has been established in the United States. In China, the production process of polymerized rosin with sulfuric acid as catalyst was studied in 1968, and the factory was established in 1973. In the early 1980s, the process with sulfuric acid-zinc chloride as catalyst was put into production. These two processes coexist in production. There are two models: 1 15 # and 140 #.
Nature and classification
Polymerized rosin has high softening point, excellent oxidation resistance, high viscosity in organic solvents, no crystallization, low acid value and good miscibility with natural or synthetic film-forming agents and rubber. Polymerized rosin has carboxyl groups, which can react to form salts, esters and alcohols. According to the different raw materials of rosin, it can be divided into polymerized rosin, polymerized wood rosin and polymerized oil rosin. According to the content of dimer, it can be divided into polymerized rosin and dimerized rosin. The former contains about 35% dimer, and the latter contains about 80%.
manufacturing technique
Taking sulfuric acid catalyst as an example, the main process conditions are as follows: ① Dissolution. Gasoline consumption (calculated by rosin) is 80 ~ 100%. ② polymerization. The dosage of sulfuric acid (calculated by rosin) is 15%, the reaction temperature is 43 3℃, and the reaction time is 2.5 ~ 3 hours. ③ washing. The oil-water weight ratio is 1∶5, the washing temperature is 60℃, and the brine concentration is 0.5%. ④ distillation. Top temperature110 2℃, bottom temperature 210 5℃, live gas pressure 78 ~ 98 kPa (upper section) and 147 ~ 176 kPa (lower section). Polymerization catalysts can be divided into two categories: one is protonic acid, such as sulfuric acid, p-toluenesulfonic acid, fluorosulfonic acid, phosphoric acid, acetylsulfuric acid, monoethyl sulfate and hydrochloric acid. One kind is Lewis acid, such as zinc chloride, aluminum trichloride, titanium tetrachloride, tin tetrachloride, boric anhydride, etc. The polymerization of rosin is a complex process, and the dimers produced have various structures, which change with different reaction conditions. With the increase of sulfuric acid concentration and dosage, the softening point of polymerized rosin increases and the acid value decreases, but the acid residue also increases, which affects the yield. With the increase of reaction temperature, the softening point of polymerized rosin increased, the acid value decreased, the output increased, but the color deepened. After 2 hours, the polymerization is almost complete, and if the time is prolonged, it has little effect on the polymerization. The color of polymerized rosin obtained by different solvents is different, and the product prepared by gasoline as solvent is the lightest.
quality index
The color shall not be lower than Grade III (sulfuric acid method) and Grade IV (sulfuric acid-zinc chloride method); Softening point (ring and ball method)110.0 ~120.0℃ (115 type),135.0 ~145.0℃ (/. Ethanol insoluble matter is not more than 0.050% (sulfuric acid method) and not more than 0.030% (sulfuric acid-zinc chloride method).
use
1 ink. Used as raw materials for gasoline photocopying ink, alcohol-soluble gravure ink, varnish ink, offset printing ink, high-speed rotary rubber color printing ink and lead printing ink, the prepared ink has good luster, fast color fixation, good color retention and strong three-dimensional effect. ② paint. The derivative of polymerized rosin (polymerized rosin ester) can be made into quick-drying alkali-resistant paint, alcohol-soluble varnish, synthetic resin varnish and so on together with other additives. ③ Adhesive. Used as tackifier in pressure sensitive adhesive and hot melt adhesive, it can improve the bonding strength and reduce the cost. ④ Other aspects. To increase the viscosity of cable impregnating oil, it can also be used in flux, paper sizing, soap, metal drier, traditional Chinese medicine wax pill, optical resin adhesive, musical instrument rosin, building materials and so on. In addition, with the approval of American Food Law, specially treated polymerized rosin and dimerized rosin esters can be used in adhesives, coatings and paper related to food packaging.