Creping Adhesive Blends for Low Moisture Tissue Production
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Solution Overview
Problem
Conventional creping adhesives become hard and less rewettable at low moisture levels, leading to blade chatter and loss of adhesion, limiting their use in manufacturing very soft tissue products that require creping at low sheet moisture levels.
Innovation Solution
A composition comprising a blend of high and low molecular weight resins, specifically glyoxylated polyacrylamide and polyaminoamide-epihalohydrin resins, applied to a creping cylinder to maintain adhesion and softness, with a molecular weight ratio of 1:99 to 99:1 and a mole ratio of epihalohydrin to secondary nitrogen atoms less than 0.5, allowing for effective creping at low moisture levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermosetting adhesives are used for creping, then adhesion strength is improved, but the coating becomes too hard and brittle at low moisture levels
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using polyaminoamide resins with specific crosslinking densities (0.1-10 mmol/g) and controlling the ratio of high to low molecular weight components. This parameter optimization allows the adhesive to maintain both strength and flexibility at low moisture levels, resolving the contradiction between adhesion strength and coating hardness.
Solution Approach 2:
The patent employs composite adhesive materials combining polyaminoamide resins with specific crosslinking agents and additives. This composite formulation creates a coating that integrates the strength benefits of crosslinked thermosetting adhesives with the flexibility needed for soft tissue production, eliminating the brittleness issue while maintaining adhesion.
2Ease of operation
If conventional adhesives are used at low sheet moisture levels, then creping process is simplified, but blade chatter and loss of adhesion occur
Solution Approach 1:
The patent optimizes adhesive parameters including crosslinking density (0.1-10 mmol/g) and molecular weight distribution to enable reliable adhesion at low moisture levels. This parameter tuning allows the adhesive to maintain appropriate flexibility and bonding strength during creping operations, preventing blade chatter while ensuring adhesion reliability without complicating the process.
3Strength
If high cross-linking thermosetting adhesives are used, then adhesion strength is improved, but rewetability and softness are reduced
Solution Approach 1:
The patent precisely controls crosslinking density parameters (0.1-10 mmol/g) to achieve the optimal balance between adhesion strength and rewetability. This parameter optimization ensures that the coating provides sufficient bonding strength while maintaining the softness and rewetability needed for high-quality tissue production, resolving the contradiction between strength and softness.
Solution Approach 2:
The patent develops composite adhesive formulations combining polyaminoamide resins with specific crosslinking agents and functional additives. This composite approach creates a coating that simultaneously delivers strong adhesion and the softness required for premium tissue products, eliminating the trade-off between strength and rewetability.
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 adhesive composition remains soft and rewettable, preventing blade wear and ensuring uniform creping, enabling the production of high-quality soft tissue products even at low moisture levels.
Implementation Method 1
The adhesion is predominantly provided by spraying an adhesive on the dryer
Implementation Method 2
the paper web has to adhere to the surface of the Yankee dryer
Data Source
AI summary
A composition comprising one or more high molecular weight resins and one or more low molecular weight resins in a ratio of about 1:99 to about 99:1 based on polymer actives, wherein said high molecular weight resins are selected from the group consisting of glyoxylated polyacrylamide, crosslinked polyaminoamide and polyaminoamide-epihalohydrin resins having a molecular weight of about 100,000 to about 5,000,000 Dalton and the low molecular weight resins are selected from the group consisting of glyoxylated polyacrylamide, crosslinked polyaminoamide and polyaminoamide-epihalohydrin resins having a molecular weight of less than about 100,000 Dalton and wherein the mole ratio of epihalohydrin to secondary nitrogen atoms in the high and low molecular weight polyaminoamide-epihalohydrin resins is less than about 0.5. and use of the composition for creping paper webs.