Study on the depositing behavior of colloidal resin in mechanical pulp

Using model solutions made up of fatty acid, resin acid and triglyceride, the effects of different composition of resin, pH value, calcium ion and temperature on the depositing behavior of colloidal resins in mechanical pulp were investigated as well as the effect of pH value on the composition of deposit with the presence of calcium ion. The results showed that for the colloidal resin, when calcium ion was not present, the deposit was relatively serious at lower pH conditions and with the increase of pH, the depositing tendency decreased gradually. The existing of calcium ion resulted in more serious resin deposit. pH value was the key factor influencing the acid resin to form calcium soap. At lower pH, hardly any calcium soap can be found in deposit and with the increase of pH, not only the content of calcium soap was improved in the deposit but also the stickiness was enhanced obviously. For the deposit of triglyceride composition, inorganic ingredient was not found. However at the range of pH4.5-8.5, the depositing of triglyceride was intensified obviously with the presence of calcium ion. Temperature has a larger effect on the depositing of resin acid composition, and with the increase of temperature the depositing behavior was enhanced due to the increase of stickiness.