Making tissue relies on the development of an adhesive coating on the creping cylinder. The coating must afford a level of protection for the Yankee surface, and it must be soft enough to allow uniform creping while preventing coating build up during the creping process. These proprieties must be designed to fit the existing processes set up to produce the desired sheet properties and support machine efficiency. This can be challenging, as the basic needs of the creping process are interrelated. This is where “Coating Space” excels by addressing the needs of the Yankee coating and by working to design the appropriate coating package. The Yankee dryer performs multiple operations in a few fractions of a second: all these requirements put different demands on the coating.

Innovations that deliver value to pulp and papermaking

Coating Space Model
Coating Space Model

Thermal – Coating dehydration and/or crosslinking, Sheet dryness and Moisture variability. Mechanical – Sheet/Coating doctoring, Surface Protection. Operational – Sheet control, Quality Parameters and Consistency. Nalco Water’s proven coating technology deliver the superior process and product performance for today’s structured and conventional tissue maker:

  • Optimized machine productivity.
  • Improved end-product performance (tissue machine & converting).
  • Expanded operating window and flexibility.

These platforms have been developed to provide higher, softer and more consistent adhesion with a wider, more manageable coating operating window. These technologies deliver good pressure roll transfer and dry-end adhesion, while providing uniform roll profile and increased tissue machine and converting productivity.

Modified Vinyl-based Polymer (MVP) Creping Technology

A proprietary creping technology based on modified vinyl-based polymers; this technology provides high adhesion over a wide range of creping moistures. Coating uniformity and softness are also improved. With its superior coating characteristics unlike conventional PAE-based adhesive chemistries, it leads to increased production performance compared to conventional and shoe-press machines. Modified vinyl-based polymers produce a softer coating film with more elasticity, reducing the need for edge sprays. Nalco Water uses the Nalco Crepe Analysis Tool to develop tissue softness in line with customer’s Emtec for TSA softness. Studies show that MVP coating technology improves the crepe structure (by increasing the crepe bars per inch) leading to improved tissue softness.

This type of coating film is good for extending blade life and reducing vibration.

New Developments – PAE improvements

  • Unique PAE construction provides the optimal balance between re-wettability and durability.
  • Superior water holding capability results in a more flexible, adhesive film.
  • Lower vibration offers better protection at a higher frequency.

Navigator technology provides tissue makers with another best-in-class Yankee coating tool, affording both performance and flexibility.
By enabling optimal performance across a varied grade structure, mill operators can increase productivity and quality: two benefits which rarely go hand in hand.

Navigator™ impact on Moisture Retention and Vibration.
Navigator™ impact on Moisture Retention and Vibration.

Proven program benefits

  • More uniform Yankee coating helps coating development/set-up.
  • Ease of operation due to softer coating characteristics, which facilitates the removal of PVOH for Structured sheet Technology.
  • Reduced dusting leads to improvements in converting runnability.
  • Delivers increased adhesion, durability and film thickness vs. alternative programs.

Nalco Water’s Machine, Operation & Chemical approach and differentiated chemistry delivers synergies across the whole paper machine allowing for further optimization
of Coating Space. This comprehensive approach has allowed for the business development on existing and new tissue machine start-ups for conventional and structured tissue machines. New technologies and the experience gained on commercial tissue machines proves that Nalco Water’s Yankee coating chemistry is successful across a wide range of process conditions.