Modeling properties of water-based paints dried by microwaves from the design and analysis of a mixture-process experiment

Abstract

Because of numerous environmental and legislative requirements the paint industry is increasing its interest in the development and production of water-based paints. Using water-based paints allows for the reduction of the emission of polluting, organic solvents found in traditional paints and varnishes. However the amount of time needed for drying these new, environmentally-friendly paints can sometimes drive down productivity. Since water is very efficiently heated by microwave energy, it seems logical that a microwave oven should be very effective for drying a waterbased paint and this topic has gained much interest in the recent past. Still, drying water-based paints using microwaves requires adapting formulations to this new technology and presents a challenge for paint formulators. This study concerns paints used in the professional, wood-finishing industry (furniture, doors, windows). This industry requires very fast surface finishing lines and waterbased paints are still a minor part of the coatings used.The objective is twofold. On one hand it is desired to understand how the major components of a water-based paint affect, alone or in combination, the major properties characterizing a good quality paint when dried by microwave energy. To achieve this, a mixture design is planned in which the quantity of each of the components varies in a domain constrained by feasibility requirements. In addition, it is wished to determine if these properties depend also upon the chemical types of binder or coalescents used in the formulation as well as upon the energy dosage received at the drying stage. It is thus necessary to combine the mixture design with a double factorial design including several types of binders and in which blends will be tested with different energy dosages.On the other hand, it is desired to use this understanding to determine which blends simultaneously optimize the eight measured properties. To achieve this, simple mathematical models of the polynomial type will be derived from the collected data and used to build response surfaces over the whole experimental domain. If such blends do not exist, an algorithm for modelling desirability will be used to come up with acceptable compromises. Approach and designThe effect of various components of water-based coatings and others factors are studied using a statistical experimental design. Not only the components (and the mixture of the components) of the paints but also the process used for drying the paints affect the final properties of the dry paint film. Such experiments where the process variables are factors that are not present in the mixtures to be studied, but whose levels, when changed, could affect the results obtained from these mixture are known as mixture experiments with process variables. This paper presents the result and the strategy of a mixture experiment with process variables consisting of six The aim of this study was to develop statistical models to optimise the performance of microwave radiation dried paints. This paper ex...