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1995
Conference Paper
Titel
Emission of pollutants from the absorbent coating consisting of alkyd resin paints during surface hardening with CO2-lasers
Alternative
Schadstoffemission von Absorptionsschichten aus Alkydharzfarben beim Oberflächenhärten mit CO2-Lasern
Abstract
Surface hardening with C02-lasers requires coatings for increasing the absorption. The coating media contain different active and binding agents, composed of organic and anorganic components. The coating is heated and pyrolysed during the hardening process. The investigations of the emitted reaction products were carried out with two alkyde resin paints selected with respect to superior infrared absorption. Aerosol and organic emission products were sampled by means of filters and absorption media during laser processing and subsequently analysed. In addition the pyrolysis was simulated and the emitted organic products were immediately analysed by a GC/MS-system. Benzene and phthalic acid anhydride as well as organic and anorganic dust were found to be the main emissions. The emission of benzene increases and that of phthalic acid anhydride decreases with rising pyrolysis temperature. The influence of pyrolysis temperature is small with low heating rate. The emission of benzene is redu ced by oxygen content in the shielding gas. The anorganic dust originates mainly from the pigment and extender substances of the paints. The emitted main components and the airborne aerosol altogether are detrimental to health. Benzene is a carcinogenic, phthalic acid anhydride is an irritating substance. The concentration of fine dust near the workpiece during laser hardening with the exhaust switched off can exceed the threshold value. Therfore exhaust and filtering are indispensible.
Konferenz
Language
English