Cationic Amylopectin Starch for Vessel Picking in Papermaking
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Solution Overview
Problem
Hardwood pulps, particularly eucalyptus, cause print quality issues due to vessel picking and ink refusal in papermaking, leading to increased costs and logistical challenges, as traditional surface sizing methods are not entirely effective and can negate the cost advantages of using hardwoods.
Innovation Solution
The use of cationic amylopectin starch in the wet-end of the papermaking process significantly reduces vessel picking, allowing for higher hardwood pulp usage without strength or quality issues, potentially eliminating the need for elaborate surface sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional surface sizing methods are used to reduce vessel picking, then print quality improves, but the cost advantage of hardwood pulps is negated and the process becomes more complex
Solution Approach 1:
The invention extracts the vessel picking problem from the papermaking process by using cationic amylopectin starch that specifically targets and binds to vessels in the wet-end, eliminating the need for subsequent surface sizing operations and their associated complexity
Solution Approach 2:
The cationic amylopectin starch is applied in the wet-end before the paper dries, performing the vessel modification action preliminarily so that vessels are already contained and bonded when the sheet forms, preventing picking issues before they occur
2Productivity
If hardwood pulp usage is increased to reduce costs, then productivity improves, but vessel picking and ink refusal problems worsen
Solution Approach 1:
The invention changes the chemical parameters of the starch additive by using cationic amylopectin with specific properties (high cationic charge density, amylopectin structure) that enable effective vessel binding at low concentrations, allowing high hardwood usage without print quality degradation
Solution Approach 2:
The cationic amylopectin starch acts as an intermediary substance that mediates between the hardwood vessels and the paper matrix, providing strong bonding that prevents picking while maintaining ink receptivity
3Reliability
If more starch is added to reduce vessel picking, then vessel picking resistance improves, but starch pick-up increases and costs increase
Solution Approach 1:
The cationic amylopectin starch exhibits local quality by specifically targeting and binding to vessels rather than uniformly distributing throughout the paper, providing concentrated vessel picking resistance where needed while minimizing overall starch consumption
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
Cationic amylopectin starch improves vessel picking resistance, enabling higher hardwood pulp usage with reduced starch pick-up and costs, maintaining paper quality without the need for extensive surface treatments.
Implementation Method 1
the specific starch used according to the invention is an cationic amylopectin starch
Data Source
Figure 1
AI summary
The invention relates to the field of papermaking. More in particular, the invention relates to a method of reducing the phenomenon of vessel picking in papermaking. In accordance with the invention it has surprisingly been found that the problem vessel picking may be significantly reduced by using a cationic amylopectin starch in the paper pulp, i.e. in the wet-end.