The Yankee dryer is a large, steam-heated, pressure vessel that is used in the production of tissue grades. Two critical operations occur at the Yankee dryer: the sheet of tissue is dried to its final moisture target, and it is creped by the creping doctor. It is the creping process which is responsible for the bulk, stretch, and softness that are desirable in tissue grades. Coating chemicals are sprayed directly onto the dryer surface after the sheet has been removed by the creping doctor. The purpose of the coating is to hold or stick the sheet to the Yankee. This affects drying because sheet adhesion affects heat transfer from the Yankee dryer shell to the sheet, and it affects creping because it affects how the sheet releases from the dryer at the creping doctor. A uniform, pliable coating produces a high quality sheet with uniform crepe, while it protects both the dryer surface and the creping doctor blade from excessive wear.
• The purpose of the Yankee dryer coating
• How the coating affects the drying and creping processes
• Common Yankee dryer coating ingredients
• Yankee coating application
