Partially Soluble Dextrins for Coating Binder Stability
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Solution Overview
Problem
Conventional styrene polymer dispersions used in coated paper production are unstable, costly due to non-renewable resources, and exhibit poor water retention, requiring continuous water addition to maintain viscosity during coating processes, which affects machineability and wet pick resistance.
Innovation Solution
Development of a modified starch with a weight-average molecular weight ranging from 250,000 to 2,000,000 Da and solubility between 50% to 85%, achieved through specific dextrinization processes involving granular starch, acidic agents, and controlled temperature and moisture conditions, resulting in high solubility and low viscosity aqueous binder compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional styrene polymer dispersions are used as binders in coating colours, then the coating process can be carried out, but the compositions exhibit poor water retention and require continuous water addition to maintain viscosity
Solution Approach 1:
The patent changes the chemical composition parameters by replacing styrene polymer dispersions with modified starches having specific molecular weights (250,000 to 2,000,000 Da) and controlled solubility (50-85%). This parameter change enables the binder to retain water effectively while maintaining appropriate viscosity for coating processes, eliminating the need for continuous water addition.
2Reliability
If high molecular weight starches are used to increase solubility, then water retention improves, but viscosity becomes excessively high and machineability deteriorates
Solution Approach 1:
The patent precisely controls the molecular weight parameter of the starch (250,000 to 2,000,000 Da) and solubility parameter (50-85%) to achieve the optimal balance. This specific parameter range allows the starch to provide adequate solubility and water retention while maintaining viscosity within the range required for good machineability in coating processes.
Solution Approach 2:
The patent uses modified starches that can be considered composite structures with controlled molecular weight and solubility characteristics. These modified starches combine the benefits of high molecular weight (improved solubility) with controlled properties that prevent excessive viscosity, achieving a composite effect that satisfies both solubility and machineability requirements.
3Ease of manufacture
If styrene polymer dispersions are used as binders, then coating can be performed, but production costs increase due to reliance on non-renewable resources
Solution Approach 1:
The patent replaces expensive styrene polymer dispersions with modified starches that are derived from renewable resources (corn, potato, wheat). These starch-based binders are more cost-effective and environmentally sustainable, eliminating the need to rely on non-renewable petroleum-based polymers while maintaining coating performance.
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 starch compositions enable high machineability in coating processes, improve wet pick resistance, and reduce production costs by maintaining high solids content and low viscosity, leading to superior coated paper properties.
Implementation Method 1
a modified starch, characterized in that it exhibits: a weight-average molecular weight ranging from 250 000 to 2 000 000 Da; a solubility, measured according to a test A, ranging from 50 to 85%
Data Source
AI summary
The subject matter of the invention is a modified starch, characterized in that it exhibits: ⋅a weight-average molecular weight ranging from 250 000 to 2 000 000 Da; ⋅a solubility, measured according to a test A, ranging from 50 to 85%. The invention also relates to a process for the manufacture of said starch and to the use thereof in the manufacture of an aqueous binder.