Moisture Curing Coatings on polyurethane

Moisture Curing Coatings on polyurethane

How can we formulate a moisture curing coating system based on polyurethane for polyethylene, PVC, Steel and Zinc substrates ?



There are plenty of these coating systems on the market to meet requirements even taking into account special applications for fabrics. For zinc there is on basic requirement, which is that the paint must not contain components which could lead to the formation of zinc soaps.

As far as the other substrate are concerned it is important to use coating systems containing groups that will promote adhesion. For steel and PVC these are prodominantly hydroxyl ( OH ) groups which normaly occur but rarely in moisture curing systems
.
For polyethylene, on the other hand, non polar groups are needed. In view of the limitations with regard to formulation possibilities, it would perhaps be best to try a range of other product such as a 40 % solution of a prepolymer in a 60/40 mixture of ethylene glycol acetate and xylene, or another propolymer, 60 % in tje same solvent blend but 1:1.

A large number of other solvents can be used, but these must be free from residual moisture. Platicisation may be necessary.




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