The results of the crushing strength tests of the coated samples produced using different proportions of sealant are shown in Fig. 6. A decrease in the crushing strength of the coated urea upon the application of the polyols was observed. At a polyol content of 1.65%, the crushing strength of the coated urea decreased dramatically from 23.6 to 3.9 N. This reduction is attributed to the destruction of the smooth coated layer by the sealant polyols.