New approach of instrumental analysis to micro spots in paper.

Abstract

Micro Spots in paper tend to appear in usage of the waste paper more than the virgin pulp as materials of paper. For the solution of problems in paper making, the causes of the micro spots should be revealed. However, in many cases, collection of the specimens are so difficult that it is hard to investigate the causes of the micro spots in paper with such ordinary methods as the observation of the spot by microscopy, UV irradiation, solvent extraction, iodine-starch reaction, ninhydrine reaction etc. This paper describes on the application of Infrared Microspectroscopy and Scanning Electron Microscope (SEM) to analyze of the micro spots in paper. Infrared Microspectroscopy was useful for the analysis of the filamentous plastic pieces, and the hotmelt pieces in paper specimen such small as 1 mm in diameter. SEM was also useful for the detection of the thermoexpandable microcapsules and the micro spots based on a piece of coating color, because the SEM gives a clear picture depending to the wide range at the depth of focus.