A MATLAB model based on the simultaneous solution of several differential equations was developed to include the impact of catalyst loading for the reactions and physical processes of a urethane box foaming process. Experiments with different amounts of catalyst loading were conducted to fit the model parameters for this thermoset polymerization. Rate constants for the polyurethane foaming reaction were determined by polyol types, catalyst types and reaction temperatures. By combining these factors polyurethane reaction rates during whole foaming process can be calculated in this model and the model can be used to predict the performance of foams which have multiple combinations of isocyanate, polyols, catalysts, chemical blowing agents, and physical blowing agents in recipes when parameters on pure component (e.g. single polyol) performance are behavior. (C) 2013 Elsevier B.V. All rights reserved.