Absorbent product
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Solution Overview
Problem
Existing methods for producing absorbent structures, such as paper towels and facial tissues, face challenges in achieving high wet strength, absorbency, and softness while avoiding undesirable byproducts like adsorbable organic halogens (AOX) from polyaminoamide-epihalohydrin (PAE) resins.
Innovation Solution
A method utilizing ultra-high molecular weight glyoxalated polyvinylamide adducts and high molecular weight anionic polyacrylamide, combined with cellulose fibers and optional additives like lignin and micro-fibrillated cellulose, to create absorbent structures without PAE, reducing or eliminating chlorinated organic compounds and enhancing wet strength through hydrogen and ionic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyaminoamide-epihalohydrin (PAE) resins are used to enhance wet strength, then wet strength is improved, but adsorbable organic halogens (AOX) byproducts are generated
Solution Approach 1:
The patent removes PAE resins from the wet strength system entirely and replaces them with alternative polymers (polyvinylamine, polyacrylamide, polyethyleneimine) that provide wet strength without generating AOX byproducts. This extraction of the harmful substance while maintaining the desired function directly resolves the contradiction between wet strength improvement and AOX generation.
Solution Approach 2:
The patent changes the chemical parameters of the wet strength system by substituting PAE resins with polymers having different chemical compositions (amine-functional polymers). This parameter change allows achieving comparable wet strength through ionic and hydrogen bonding mechanisms without the halogenated chemistry that produces AOX byproducts.
2Productivity
If conventional wet crepe processes are used for production, then productivity is improved, but web thickness and absorbency are reduced due to web compaction
Solution Approach 1:
The patent changes the dewatering parameter from mechanical pressing (conventional wet crepe) to through-air drying. This parameter change allows moisture removal without applying compressive forces that compact the web, thereby maintaining web thickness and absorbency while still achieving high production speeds through efficient air drying.
Solution Approach 2:
The patent replaces the mechanical pressing system with a through-air drying system that uses air flow rather than mechanical compression to remove moisture. This substitution eliminates web compaction while maintaining productivity, as the air drying process can operate at high speeds without mechanically compacting the absorbent web.
3Use of energy by moving object
If mechanical pressing is used to remove moisture, then energy consumption is reduced, but web thickness and absorbency are lowered
Solution Approach 1:
The patent changes the moisture removal parameter from mechanical compression to thermal drying through air flow. This parameter change accepts higher energy consumption for drying but preserves web thickness and absorbency by eliminating the compaction effect of mechanical pressing, achieving a different optimization balance.
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 method produces absorbent products with high wet strength, absorbency, and softness, achieving tensile strengths comparable to PAE-containing products while minimizing or eliminating chlorinated byproducts, thus improving environmental and operational safety.
Implementation Method 1
enhancing wet strength through hydrogen and ionic bonding
Implementation Method 2
enhancing wet strength through hydrogen and ionic bonding
Implementation Method 3
nearly half of the water removed from the web is through drainage and mechanical pressing
Implementation Method 4
The web is then dried and creped from the Yankee Dryer
Data Source
AI summary
A method of making an absorbent structure including mixing ultra-high molecular weight (“UHMW”) glyoxalated polyvinylamide adducts (“GPVM”) and/or high molecular weight (“BMW”), glyoxalated polyacrylamide and/or high cationic charge glyoxalated polyacrylamide (“GPAM”) copolymers and high molecular weight (“BMW”) anionic polyacrylamide (“APAM”) with the furnish during stock preparation of a wet laid papermaking process.