Vinylamine Adhesive Coating for Yankee Dryer Buildup Control
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Solution Overview
Problem
Current creping adhesives, particularly polyaminoamides crosslinked with epichlorohydrin, tend to build up on Yankee dryers, causing blade chatter and sheet defects, and do not consistently provide the desired combination of adhesion, durability, and softness across all tissue grades and conditions.
Innovation Solution
A method using an adhesive composition with a pH of 6.5 to 8, comprising vinylamine/N-vinyl formamide polymers, which are crosslinked with polyvinyl alcohol and other polymers, and optionally including additional agents like plasticizers and fluorescent tracers, to enhance adhesion and durability while preventing buildup on the creping cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyaminoamides crosslinked with epichlorohydrin are used as adhesives, then adhesion and durability are improved, but coating buildup occurs causing blade chatter and sheet defects
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using vinylamine/N-vinyl formamide polymers with specific monomer ratios (10-99 mole percent vinylamine, 90-1 mole percent N-vinyl formamide) and controlling pH (6.5-8), which fundamentally alters the coating properties to prevent buildup while maintaining adhesion and durability
Solution Approach 2:
The patent creates a composite adhesive system by combining vinylamine/N-vinyl formamide polymers with polyvinyl alcohol and other polymers, forming a multi-component coating that achieves the desired balance of adhesion, durability, and anti-buildup properties
2Reliability
If the adhesive coating is made harder to improve durability, then durability is improved, but blade wear and sheet defects increase
Solution Approach 1:
The patent adjusts the hardness parameter of the coating by controlling the polymer composition and crosslinking density, creating a coating that is durable yet sufficiently soft to prevent blade chatter and wear
3Object-generated harmful factors
If the adhesive coating is made softer to reduce blade wear, then blade wear is reduced, but coating durability decreases
Solution Approach 1:
The patent uses a composite coating system where polyvinyl alcohol provides softness and vinylamine/N-vinyl formamide polymers provide durability through crosslinking, achieving both reduced blade wear and maintained coating durability simultaneously
4Reliability
If polyvinyl alcohol is added to the adhesive composition, then coating softness and durability are improved, but the complexity of the composition increases
Solution Approach 1:
The patent merges multiple functional polymers into a single integrated adhesive composition, where vinylamine/N-vinyl formamide polymers and polyvinyl alcohol work synergistically to provide both softness and durability, simplifying the overall system despite the multi-component nature
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 provides improved adhesion and durability, reducing blade wear and sheet defects, and maintains effectiveness under the challenging conditions of the TAD process, with enhanced stability and performance compared to traditional adhesives.
Implementation Method 1
The adhesion is provided by applying an adhesive to the dryer
Implementation Method 2
comprising one or more vinylamine/N-vinyl formamide polymers... and optionally including additional agents like plasticizers and fluorescent tracers
Data Source
AI summary
This invention is method of creping a paper web comprising a) applying to a rotating creping cylinder an adhesive composition having a pH of about 6.5 to about 8 and comprising one or more vinylamine/N-vinyl formamide polymers composed of about 10 to about 99 mole percent vinylamine monomer and about 90 to about 1 mole percent N-vinylformamide monomer; b) pressing the paper web against the creping cylinder to effect adhesion of the paper web to the creping cylinder; and c) dislodging the paper web from the creping cylinder with a doctor blade.