Using the form of harvesting and cutting to collect turpentine and then processed and refined rosin called fat rosin. It is characterized by continuous harvesting of pine trees, which is conducive to the full utilization of resources. China is rich in turpentine resources, is the largest production of rosin, rosin production in a fairly long time will remain more than 350,000 tons. Therefore, it is estimated that in the next 20-30 years, the world's annual output of rosin can still be maintained at 65-70 million tons.
(2) wood rosin
It is the pine root or trunk chopped up, with a solvent soaked in resin, processed and refined out of rosin. Mainly produced in the United States
, the raw material depends on the country's southeastern original pine forests, now due to the reduction of forest resources, resulting in a shortage of wood rosin raw materials, production from 316,000 tons in 1950, down to 20,000 tons. The former Soviet Union also produces wood rosin, due to the reduction of resources, production has also declined sharply. Estimates of the world now wood rosin production only accounted for less than 5% of the total rosin.
(3) oil rosin
From the wood pulp and paper industry, from the sulfate pulp back to the black liquid processed and obtained, the original performance is not as good as rosin, and later due to the continuous improvement of quality, now the performance of rosin and rosin similar. As a result of the proportion of pine used in papermaking is reduced, reducing the rosin yield from oil slick fractionation (from 27% to 21%). So in recent years, although the crude oil slick fractionation capacity increased, but the oil slick rosin production is still only relatively stable, accounting for about 30% -35% of the total rosin.
There are two major types of turpentine processing methods in mainland China: the drip method and the steam method. Drip method of turpentine in the distillation pot, - side with direct fire heating, - side drops of water to accelerate the turpentine vaporization, turpentine and turpentine vaporized rosin. Drip method rosin is also called the soil method rosin, due to equipment and process is simple, quality is not stable, darker color or softening point is lower, but the price is cheap. Steam method is the use of superheated steam production rosin, quality and stability of the softening point is high, light color impurities, suitable for export
, the price is higher than the drip method rosin. The same - level rosin, drip method and steam method quality is very different, businessmen in the purchase - must distinguish clearly.