Modified Lignocellulosic Pulp Wet-Strength via Anhydride Treatment
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Solution Overview
Problem
Current methods for achieving high wet-strength in paper products require the addition of wet-strength resins in high amounts, making the manufacturing process expensive and inefficient.
Innovation Solution
A method involving the addition of a dicarboxylic acid anhydride to dry lignocellulosic pulp to increase its negative surface charge, which enhances wet-strength properties without the need for excessive wet-strength resins, achieved through drying the pulp to at least 85% dryness and treating it with dicarboxylic acid anhydrides like maleic anhydride, followed by beating to activate the pulp's wet-strength properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wet-strength resins are added in high amounts to achieve high wet-strength, then wet-strength is improved, but manufacturing cost increases
Solution Approach 1:
The invention changes the chemical parameter of the pulp by introducing negatively charged groups through reaction with dicarboxylic acid anhydrides or polyacrylic acid. This chemical modification enables the pulp to achieve high wet-strength without requiring high amounts of external wet-strength resins, thus resolving the contradiction between strength improvement and resin quantity reduction
Solution Approach 2:
The pulp is modified to possess intrinsic wet-strength properties through chemical treatment, making it self-sufficient in achieving wet-strength without relying on external resin additives. The modified pulp fibers themselves provide the wet-strength through their altered surface charge and enhanced bonding capabilities
2Strength
If dicarboxylic acid anhydride is added to increase negative surface charge, then wet-strength is improved, but chemical treatment complexity increases
Solution Approach 1:
The pulp is dried to at least 85% dryness before chemical treatment, which prepares the pulp in an optimal state for subsequent reaction with dicarboxylic acid anhydride. This preliminary drying step facilitates better chemical penetration and reaction efficiency, simplifying the overall treatment process while achieving the desired wet-strength improvement
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 modified pulp exhibits substantial increases in wet-strength, as evidenced by higher wet tensile strength indices, even without the addition of wet-strength resins, thereby reducing production costs and improving paper product quality.
Implementation Method 1
adding a dicarboxylic acid anhydride, particularly with a molecular weight of 220 g/mol or less, to the dry pulp in an amount and under conditions to obtain a modified pulp having a negative surface charge of at least about 8 μmol/g
Data Source
AI summary
A method for producing a modified lignocellulosic pulp having improved wet-strength properties and a modified lignocellulosic pulp obtainable by the method.