Tree Rosin is called gum rosin, which is obtained by collecting pine resin in the form of harvesting and then processing and refining it. Its characteristic is that the pine trees can be harvested continuously, which is conducive to the full utilization of resources. China is rich in rosin resources and is the country with the largest production of gum rosin. The output of gum rosin will remain above 350,000 tons for quite a long time. Therefore, it is estimated that in the next 20-30 years, the annual output of gum rosin in the world can still be maintained at 650,000-700,000 tons.
Tree Rosin is made by chopping pine roots or tree trunks, leaching the resin with solvent, and extracting it through processing. Mainly produced in the United States, the raw material depends on the original pine forest in the southeast of the country. Now due to the reduction of forest resources, the raw material of wood rosin is in short supply. The output has dropped from 316,000 tons in 1950 to 20,000 tons at present. The former Soviet Union also produced wood rosin, but due to the reduction of resources, the output also declined sharply. It is estimated that the world’s existing wood rosin production only accounts for less than 5% of the total rosin.
It comes from the wood pulp and paper industry, and is processed from the black liquor returned from kraft pulping. Its performance is not as good as that of gum rosin. Later, due to the continuous improvement of its quality, its performance is now similar to that of gum rosin. The yield of rosin from tall oil fractionation was reduced (from 27% to 21%) due to the reduction in the proportion of pine wood used in papermaking. Therefore, although the fractionation capacity of crude slick oil has increased in recent years, the output of slick oil Tree Rosin has remained relatively stable, accounting for about 30%-35% of the total rosin.
Attachment: drip method and steam method
In mainland China, there are currently two types of rosin processing methods: “drip method” and “steam method”. The “drip method” is to put turpentine in a distillation pot, heat it with direct fire on one side, and drip water on the other side to accelerate the vaporization of turpentine, and steam the turpentine to obtain rosin. “Drip method” Tree Rosin is also called “earth method” rosin. Due to the simple equipment and process, the quality is not stable, the color is darker or the softening point is lower, but the price is cheap. The “steam method” uses superheated steam to produce rosin, which has stable quality, high softening point, light color and less impurities, and is suitable for export. The price is higher than that of “drip method” rosin. The quality of “drip method” and “steam method” are quite different for the same grade of “rosin”, so merchants must distinguish clearly when purchasing.
At present, most of the Tree Rosin in my country is directly used in the production of paper, paint, soap and ink. Because rosin has the disadvantages of easy oxidation and low softening point, the paint industry often uses the carboxyl reaction of resin acid to make resin ester and resin. Resinate, and then reuse; while the synthetic rubber and ink industries use the double bond reaction of resin acid to make disproportionated rosin, polymerized rosin, hydrogenated rosin, etc. for reuse.
