Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2002

Curing Time of Polyurethane Coatings

Q. Could you please give us some advice on possible methods that would shorten the curing period of a polyurethane coating applied to a fabric-like substrate? We are thinking about some catalysts but have not been able to found one suitable for our method. Our actual method takes about 30 hours for cure and our plant layout is becoming a restraint.

A. I presume you have already spoken to your paint vendor and asked for advice on shortening the curing time. Therefore, assuming you have already done this, you can also shorten the curing time by heating the coating as it is being applied or after it has been applied. If you do this, make sure that you have adequate airflow over the substrate so that you can get all the solvents to evaporate before they become entrapped in the coating. The higher the temperature of the coating, the shorter its curing time.

If you decide to heat the coating before it is applied, be careful that the curing time is not so short that you will plug up the spray equipment, hoses, etc.