Paper360 - March/April 2012 - (Page 52)

TISSUE TECHLINK An INNOVATIVE Yankee COATING Program A new option lets tissue makers rethink how they manage their coating systems KEVIN BRENNAN C ompetition within the global tissue industry continues to be fierce as new tissue capacity comes online and consumers demand improved quality. Demands for quality have driven the proliferation of through-air-dry (TAD) assets in the private label market. In addition, largely driven by cost and green initiatives, more recycled fiber is being utilized in the manufacture of tissue. Because each of these market trends have a dramatic effect on the Yankee coating, tissue makers are dis- covering that they need to rethink how they manage their coating systems. To achieve their quality goals, tissue makers must carefully manage quality parameters such as bulk, stretch and hand feel. These parameters can be modified through lower moisture and higher adhesion levels on the Yankee. In addition, a higher wet-to-dry strength ratio can be achieved in the sheet by utilizing temporary wet strength (TWS) agents, debonders and spray softeners. However, this approach can challenge the Yankee coating because some of the polyacrylamide chemistry of the TWS product transfers to the Yankee surface and forms a more brittle, uneven coating that doctors poorly. Yankee surface temperatures associated with the low moistures and development of hand feel cause the coating to reach very high viscosities in small areas causing sheet picking. In addition, the coating becomes difficult to doctor evenly, which can aggravate chatter, especially on machines that have a history of chatter caused by mechanical issues. Figure 1. The Yankee coating was brittle and chatter was developing. 52 Paper360º MARCH/APRIL 2012

Table of Contents for the Digital Edition of Paper360 - March/April 2012

Over the Wire . . . News Summary
Asian Innovation on the Rise
SPECIAL FEATURE: Tissue Industry
North America Shifts to Specialization
A Measured Success
Aligning Rolls in a Paper Machine Winder
Understanding Lightweighting
Sappi Biberist Tests a New Inline Sensor to Control OBAs and Colors
Process Control for Stickies
An Innovative Yankee Coating Program
Biopolymers in Papermaking
Best Practices in Product Development
Employee Work Restrictions Challenge Human Resources
Paper360° Online Exclusives
Association News

Paper360 - March/April 2012