Studies of orange peel formation in high-speed film coating

Misting and orange peel formation, the two dominant runnability and quality issues in high-speed film coating, originate from the film splitting of co ating color in the application nip. A great deal of work has been directed at understanding misting on high-speed film coaters, but much less work has been reported on the factors that impact orange peel formation. This study is part of a more systematic evaluation of the factors controlling orange peel formation in high-speed film coating. The effect of coating color, bas e paper, and machine variables on the orange peel pattern has been studied experimentally. We used Prufbau printed strips to evaluate the degree of orange peel format ion. The relationship between orange peel formation and coating variables i s complex. In some cases, orange peel and misting are correlated, while in other cases, they are not. Increasing coating solids decreased both misting and orange peel formation. The degree of orange peel also depends on the s peed at which the coating levels after the firm splitting in the applicatio n nip.