Composite Sizing Agent for Aseptic Paperboard Penetrant Resistance
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Solution Overview
Problem
Aseptic packaging boards face challenges in resisting both hot hydrogen peroxide solutions used for sterilization and lactic acid-containing liquids, with existing dual sizing systems being less than optimal due to pH compromises and requiring cumbersome inventory and metering of multiple sizing agents.
Innovation Solution
A process involving an aqueous emulsion of a reactive sizing agent blend comprising at least 30% fatty acid anhydride and alkyl ketene dimer, combined with an insolubilizing agent like alum or polyaluminum chloride, added to the pulp slurry at a near-neutral pH, enhances resistance to both hot hydrogen peroxide and lactic acid solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual sizing system using both AKD and rosin is used to provide resistance to hot hydrogen peroxide and lactic acid, then resistance to both penetrants is improved, but system complexity and inventory management become cumbersome
Solution Approach 1:
The patent combines rosin and AKD into a single composite sizing agent where rosin is chemically attached to AKD molecules. This merging allows both sizing agents to be applied simultaneously in a single step rather than requiring separate application systems, thereby maintaining resistance to both hot hydrogen peroxide and lactic acid while simplifying the sizing system
Solution Approach 2:
The composite sizing agent performs multiple functions simultaneously: it provides resistance to hot hydrogen peroxide through the rosin component and resistance to lactic acid through the AKD component. This multi-functionality eliminates the need for separate sizing systems for different penetrants, reducing system complexity while maintaining comprehensive protection
2Reliability
If a dual sizing system with both AKD and rosin is used to achieve resistance to both penetrants, then sizing performance is improved, but the number of sizing agents to be inventoried and metered increases
Solution Approach 1:
By chemically combining rosin and AKD into a single composite sizing agent, the patent reduces the number of separate chemicals that need to be inventoried and metered from two to one. This merging simplifies inventory management and metering operations while maintaining the sizing performance benefits of using both agents
3Adaptability or versatility
If a compromise pH of about 6.5 is used for dual sizing to balance both AKD and rosin efficiency, then both sizing agents can be used, but sizing efficiency is reduced compared to optimal pH conditions
Solution Approach 1:
The patent changes the chemical structure and bonding parameters of the sizing system by chemically attaching rosin to AKD. This structural modification allows the composite agent to maintain high sizing efficiency across a broader pH range, eliminating the need to operate at a compromise pH and enabling optimal performance at the natural pH of the pulping process
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 superior resistance to hot hydrogen peroxide and lactic acid, outperforming individual sizing agents and dual systems, with improved performance at reduced pH compromise and simplified inventory management.
Implementation Method 1
A reactive sizing agent is one that chemically reacts with cellulose
Implementation Method 2
an insolubilizing agent selected from the group consisting of alum (aluminium sulfate) and polyaluminium chloride (PAC)
Data Source
AI summary
A process to increase the resistance of paper board to hot penetrants using a sizing agent containing fatty acid anhydride, and an insolubilizing agent is disclosed. Additionally, a composition useful to impart hot penetrant resistance is disclosed.