Implementação de um método para a medição de Gel Time de resinas à base de formaldeído

EuroResinas – Industrias Químicas S.A. (a company of the Sonae Arauco group) produces thermosetting resins for various applications, such as production of laminates, wood panels, among others. One important characteristic of these resins is the Gel Time and it is therefore essential to determine it. At industrial level, the Gel Time is a critical characteristic because it is the time that it is no longer possible to handle the resin. This characteristic is also important because it allows to obtain catalysis curves which serve to determine the amount of catalyst that optimizes the curing time of the resins. The main porpoise of this work is to put in work a new Gel Time measuring equipment, present in the development laboratory of Sonae Arauco, ensuring the efficiency of the measurement process. The strategy suggested for this implementation is the study of this characteristic using the equipment GELNORM® Gel Timer TC Gel Instruments AG. This characteristic is essentially determined for the application of resin in the impregnation of paper. Thus it is intended to analyze the thermosetting resins present in the portfolio of EuroResinas Industrias Químcas S.A. those resins are 4 phenol formaldehyde, 1 melamine formaldehyde resin and 1 urea formaldehyde resin. During the first phase of the work, this being the main one, several tests were performed at a constant temperature of 121 ° C (standard temperature for the equipment present in the quality control laboratory of EuroResinas) for 4 phenolic resins (encoded as A, B, C and D) and for a melamine-formaldehyde resin (E) and a urea-formaldehyde resin (F) in order to achieve the objective of the study. After obtaining the values of the tests, a statistical treatment was applied to them. Regarding the results obtained with the equipment in study, in order to evaluate trough the test of hypothesis of two means if the resin mass influences Gel Time, many tests were performed with masses of approximately of 5, 7,5 and 10 grams. It was observed that for all the phenol formaldehyde resins and melamine formaldehyde resin the mass of the samples used did not influence the results obtained. The comparison of inter-laboratory results showed that for phenol formaldehyde resins, the averages of the different devices were statistically different, however, for the melamineformaldehyde resin, are equal. EuroResinas – Industrias Químicas S.A. also possesses another laboratory that has a different equipment (Sunshine GEL TIME METER) that measures this characteristic. Data obtained with this equipment was also studied. The inter-laboratory comparison has shown that for the phenol-formaldehyde resins the mean of the equipments was statistically different, however for the melamine-formaldehyde resin was equal. It was found that for the type A resin the average Gel Time for the entire mass of 5 grams was 14,4 ± 0,6 minutes and the mean of Gel Time of the other laboratory was 10,8 ± 0,3 minutes. As for the type B resin for the samples with approximate masses of 5 grams, the average Gel Time was 17,9 ± 0,9 minutes and the mean of Gel Time measured on the equipment in other laboratory was 14,8 ± 0,6 minutes. The average Gel Time of the type C resin for the mass of 5 grams was 18,5 ± 0,7 mi and the mean of Gel Time measured in the equipment of the other laboratory was 12,8 ± 0,5 minutes. The average Gel Time for the type D resin when the masses were approximately 5 grams was 20,8 ± 0,9 min, for the masses of 7,5 grams the average Gel Time was 21,1 ± 0,9 minutes and the mean Gel Time measured in the equipment of the other laboratory was 16,6 ± 0,4 minutes. As of the E resin, the average for the mass of 5 grams was 48,1 ± 0,9 minutes and the mean of the results obtained in other equipment was 48 ± 2 minutes. In regards to the urea-formaldehyde resin (F), it was concluded that this equipment was not suitable to evaluate the Gel Time of this resin. The second phase of the work consisted in a catalysis curve of the E resin and where an exploratory study was done. The curves by both equipments were similar since both curves had the same tendency. It showed that the amount of catalyst that must be used for industrial application of the E resin should be between 0,2 % 0,3 % if the Gel Time is measured in the other equipment. To reach a conclusion on the equipment under study, more points would need to be made , but the order of magnitude would be the same.