Study on Corrosion Preventive Treatment of Steel Pipes by UV Curable Coating (IV)

Effect of Curing Condition on Coating Properties of UV Curable Resins for Steel Pipe Protection

Abstract

Effect of the kind of the UV source and curing temperature on coating properties has been investigated on two types of UV resins, which have been prepared for the temporary rust prevention coating of steel tube and the primer of polyethylene anticorrosion coating for steel pipe.
As for the UV source, high pressure mercury lamp and metal halide lamp have been comparatively estimated. The former has had high curing efficiency of the coating surface to have high UV energy distribution in the range from 200 nm to 320 nm. The latter has had high curing efficiency of the coating bottom to have high UV energy distribution over 330 nm. In order to estimate the effect of the UV wave length on the curing, many researches have been done with the EXCIMER laser UV radiation equipment which has oscillated UV ray of single wave length. From the result, it has been found that UV rays of the shorter wave length have been able to cure the surface of the coating more effectively than UV rays of the longer wave length and UV rays of over 330 nm have been able to cure the bottom of the coating where has been over 10 μm depth.
And it has been found that heating the coated material has made the cure degree of the coating higher to decrease the viscosity of the coated UV resin. The heating effect has been found at the temperature range where the viscosity has been over 3000 cps. So, in the case of the high viscosity, over 3000 cps, UV resin coating, the high temperature UV radiation has been thought much effective to cure the coating in the state of high cure degree.