QUANTITATIVE ANALYTICAL METHOD FOR CARBON BLACK

摘要

PROBLEM TO BE SOLVED: To realize a quantitative analytical method in which an analyzed value of high accuracy is given without being affected by a nonmagnetic support and a magnetic powder when carbon black in a magnetic recording medium is quantitatively analyzed. ;SOLUTION: A video tape from which a back layer is removed is immersed in hydrochloric acid. A magnetic powder is dissolved, removed and washed by water. After that, the video tape is immersed in an organic solvent so as to be separated into a base tape and a magnetic layer from which the magnetic powder is removed. The obtained magnetic layer from which the magnetic powder is removed is dried. Thereby, a thermal analytical sample is obtained. The sample is heated to a temperature of about 600°C by a differential thermobalance while nitrogen gas is flowing into. An organic substance such as a binder or the like is thermally decomposed. The sample is cooled once to a temperature of about 350°C, and it is then heated to a temperature of about 800°C while air is flowing into. Carbon black is burned. On the basis of a reduction in the weight of the sample at respective stages during this time, the carbon black is quantitatively determined.;COPYRIGHT: (C)1999,JPO