Method for determining the production parameters for a substrate coating process

摘要

A method to evaluate, determine and optimize production parameters for a coating application of a UV cationic polymerizable coating system to a substrate is provided. The method is based on a simulation model which includes both shadow and dark cure processes. Both of an active center generation process and the active center diffusion process are mathematically described. In the model, the two processes are considered separately since they are driven by different fundamental phenomena and occur on different timescales. Evaluation or prediction of the effect of process variables on the curing of a cationic coating of a complex substrate according to the described method allows characterization and understanding of process variables which may save set-up costs and improve production efficiency.

主权项

1. A method for evaluating a UV polymerizable cationic system for coating performance on a substrate, comprising:
a) selecting a UV polymerizable cationic system to investigate for coating performance; b) identifying or selecting core and mesh variables for the selected UV polymerizable cationic coating system; c) estimating a coating cure for the selected UV polymerizable cationic coating system in spatial dimensions of depth and width by numerical solution of a Polychromatic Governing Set of Equations based on the identified core and mesh variables; and d) evaluating the selected coating system based on the obtained estimated cure depth and width; wherein the Polychromatic Governing Set of Equations calculates a concentration of cationic active centers produced during a UV illumination period and in addition, a diffusion of the cationic active centers in the two spatial dimensions during a specified period of time following termination of the illumination is calculated according to equation (5):
∂Cac(t,x,z)/∂t=Dac[∂2Cac(t,x,z)/∂x2+∂2Cac(t,x,z)/∂z2]  (5) wherein Cac(t,x,z) is the active center molar concentration at time t, depth z and width x, the value of Cac at termination of illumination is of a magnitude of 10−3 to 10−2 mol/L, and Dac is the diffusion coefficient of the active center post illumination in units of length2/time.