Abstract
Not only the unbleached sulphite pulp often causes the pitch trouble in summer, but the rosin size in bleached sulphite pulp causes the same pitch trouble very suriously.The latter is more severe than the former. The rosin; dark and brittle, showed M.P. 8083deg;C. In these two kinds of rosin contained Ca+Zn and Fe respectively. It is 318deg;C higher than usual Japanese rosin. In the ash of rosin, Ca Zn Fe Si Al were detected mainly. These two kinds of rosin contained Ca+Zn or Fe respecti vely.
By the vacuum distillation of terpentine (from Pinus Thumbergii) the distillate was gained as the standard pale rosin (M.P.73deg;C, ash 0.00%). The impure rosin are made to contain resinate as 0.2% of inorganic oxide, from the standard pale rosin.
The resinate shows M.P. 7880deg;C. By using the size-pitch-determining-appartus which was devised by the author, the rosin was found to cause the severe pitch trouble respectively. From these two points, the two kinds of rosin were thought to contain Ca+Zn or Fe resinated respectively. From the standpoint of pitch trouble, the M.P. of rosin should be 6575deg;C, and yet if the ash content of rosin is the less, the better it will be.
