Segmented Fibrous Web Reel Coatings for Tear Prevention
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Solution Overview
Problem
In the paper industry, fibrous webs tend to tear during reel change-over due to free movement of web ends, leading to damage, and existing methods like rubber layers and adhesives are not reliable in preventing web discharge into the pulper during transfer from full to empty reels.
Innovation Solution
A reel with an outer surface formed by multiple axial coatings of different materials, where the center coating is smoother and more elastic than the outer coatings, allowing better adhesion and easy separation of the web tip during winding and unwinding, and featuring a PTFE adhesive tape for enhanced adhesion and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single uniform coating is used on the reel surface, then the manufacturing process is simple, but the adhesion of web tip is insufficient and web ends move freely causing tears
Solution Approach 1:
The reel coating is divided into multiple axial segments with different properties: a center coating portion and outer coating portions. Each segment serves a specific function - the center portion provides high adhesion for web tip securing, while outer portions provide release properties for easy web removal after winding.
Solution Approach 2:
Different regions of the reel surface are given different coating properties tailored to local requirements. The center coating has high adhesion characteristics specifically where the web tip contacts during startup, while outer regions have low adhesion characteristics for easy web release during normal operation.
2Reliability
If adhesive strips or viscous adhesive are used to secure web ends, then web adhesion is improved, but web discharge into pulper cannot be reliably prevented and causes damage
Solution Approach 1:
The coating properties are carefully controlled within specific parameter ranges: center coating roughness Ra of 0.05-0.5 μm (smoother than outer coatings), center coating thickness of 0.5-5 mm, and specific hardness values. These parameter optimizations ensure reliable web tip adhesion during transfer while preventing web discharge into the pulper.
3Reliability
If the coating surface is rough, then web adhesion is strong, but web separation during unwinding is difficult
Solution Approach 1:
The coating is segmented into center and outer portions with opposite surface characteristics. The center coating has smooth surface (Ra 0.05-0.5 μm) for easy web separation, while outer coatings have rough surfaces for strong web adhesion during winding operations.
Solution Approach 2:
The smooth surface property is localized specifically to the center coating portion where web tip contact occurs during startup and separation. The outer coating portions maintain rough surfaces for optimal web adhesion during the winding process, achieving both easy separation and strong adhesion in different locations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures reliable adhesion and easy separation of the fibrous web tip, preventing tears and web discharge into the pulper, thereby improving the quality of the wound roll and reducing damage during reel change-over.
Implementation Method 1
the axially centered coating should consist partially to entirely of polytetrafluoroethylene ('PTFE')
Implementation Method 2
the axially centered coating should have higher elasticity than the axially outer coatings
Data Source
AI summary
The invention relates to a spool for winding a fibrous web, the lateral surface of which is formed by a coated spool core. The aim of the invention is to improve the winding quality by the fact that the outer lateral surface is formed by a plurality of separate coatings which are arranged axially next to one another, of which at least two adjacent coatings are made of different materials.