Dielectric analysis as cure monitoring system for melamine-formaldehyde laminates

Autor: Marlen Reiner, Elisabeth Dolezel-Horwath, Claudia Pretschuh, Uwe Müller, Stephan Knappe, Edith Zikulnig-Rusch
Rok vydání: 2016
Předmět:
Zdroj: Progress in Organic Coatings. 90:277-283
ISSN: 0300-9440
DOI: 10.1016/j.porgcoat.2015.10.019
Popis: Combinations of aminoplastic thermosetting resins are used for the production of the majority of laminates. The binder's degree of curing is the key factor for the quality of laminates. Dielectric analysis (DEA), a method well-known for the curing characterization of coatings, represents an interesting way for online cure monitoring of aminoplastic resins. By measuring the dielectric properties, process-related variations in the curing behavior can be detected directly during the production. In the present study, the applicability of DEA to papers impregnated with melamine-formaldehyde (MF) resins has been tested. Analyses were carried out during the hot pressing process, and the effects of time and temperature variation were shown. The degree of curing was determined from the changes in ion viscosity. Interestingly, the majority of the cross-linking occurs mainly after the actual hot pressing. The degree of curing determined in a second pressing/measurement cycle correlates well with the laminate's surface properties.
Databáze: OpenAIRE