Featured Stories
Show Preview | INFOFLEX 2018 Collocates with Forum in Indianapolis
More than 240 exhibitors from every facet of the package printing [ampersand] converting industries will meet more than 2000 attendees.
Read moreCoating Matters | The 6 C's of Roll-to-Roll Coating Systems
Develop a balanced approach to precision coating by understanding these six areas of concentration.
Read moreRDG Media Purchases Paper, Film & Foil Converter (PFFC)
PFFC will be the lead brand for RDG Media products.
Read moreLabel PRomotion | Too Little, Too Much 'Sticktoitiveness' Sully Label Appeal
In addition to preventing a negative experience, addressing adhesives can provide sales opportunities.
Read more
News | New Products
-
BALDWIN Acquires Digital Ink System
An agreement with Quad/Graphics results in the acquisition, allowing BALDWIN to continue development for packaging, corrugated, and more
-
DowDuPont to Invest in Expansion
The company will invest $100 Million to expand manufacturing capacity of specialty materials at Sabine River Works
-
Monadnock Announces Label Product
Envi 96 Label, part of company’s EnviPortfolio line of substrates, is said to offer high performance as well as graphics that “pop”
-
New Era Partners with Adept Converting
New Era will service clients of Adept, a manufacturer’s representative, with both companies excited to bring their expertise together
-
Flint Announces New-Generation Sleeves
The rotec Smart Sleeve and rotec High Performance Sleeve are said to provide easy mounting and superior performance
-
Iggesund Invercote Paperboard Used for Jimmy Choo Perfume Box
Draeger converted carton for Interparfums
-
Teknek Distributor Adds to Demo Facility
JK Innotion, company’s Korean distributor, adds a TWC web cleaner to demonstrate its benefits
White Papers
• Designing a Successful Retort-Grade Packaging Structure
• Hermetic-Seal Performance of BOPP Laminate Structures in VFFS Pouch Applications
• Methods and Design Considerations for the Application of Hot Melt Coatings
• BOPP Laminate Structures for “Over-the-Mountain” VFFS Pouch Applications
Expert Advice
WebHandlersQuiz #18: Which Rolls Tighter—Paper or Film?
- Published: August 10, 2012
WebHandlersQuiz 18 continues the Q&A format I began this past February with our quest to address fundamental questions concerning web handling. To see past Quiz questions and answers, visit: pffc-online.com/blog/walker.
So this blog posting continues to focus on the subject matter we began in July, which is Winding–If you wind a paper and a film product of equal thickness and roll geometry at the same combination of winding conditions (tension, nip, taper, speed), which will likely have higher internal roll pressures or greater tightness?
The mostly likely answer is the film product will wind a much tighter roll, especially if it is a lower modulus film, such as polyethylene or polypropylene.
Paper products tend to wind looser rolls since they have a high relative compressibility in the radial direction, and the web stretch (a.k.a. strain) in the paper layers can lose their tension from radial shifting or compressing of the roll’s core and inner layers.
Film products tend to wind tighter rolls since they have a low relative compressibility in the radial direction, and the web strain (especially in stretchy films) in the film will have minimal tension loss from radial shifting or compressing of the roll’s core and inner layers.
One exception might be high speed winding of a smoother film without control of the entrained air layer compared to a more porous paper. While paper can absorb an entrained air layer, films will capture the air between layers. Over time, the air can bleed out of a film roll, causing it to loosen and potentially giving rise to a looser condition than paper on the same winder.
More on this topic was covered in this archived Web Lines column: The Pressure of Winding Rolls, May 2006.
Stay tuned to this blog for more Q&A. My next Quiz will feature still another facet of Winding involving the advantages of using a nipped or gap-controlled roller ahead of winding.