High Amylopectin Dextrin Coating Binders for Viscosity Control
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Solution Overview
Problem
The paper industry faces challenges in replacing synthetic latexes with natural binders that provide stability, rheological compatibility, and water retention in coating colors, particularly due to issues like retrogradation and high viscosity, which affect handling and application processes.
Innovation Solution
A coating color composition utilizing dextrins with high amylopectin content, exceeding 95%, and weight-average molecular weights between 600,000 and 2,500,000 Da, which enhances stability and offers a better compromise between viscosity and water retention, allowing for improved handling and application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If starch or its derivatives are used as natural binders to replace synthetic latexes, then environmental sustainability is improved, but retrogradation occurs during cooling causing sudden increase in viscosity
Solution Approach 1:
The patent changes the molecular weight parameter of the dextrin binder to between 600,000 and 2,500,000 Da, which is significantly higher than conventional starches. This parameter change fundamentally alters the rheological behavior of the adhesive, preventing retrogradation-induced viscosity spikes while maintaining stability and natural origin benefits.
2Quantity of substance
If conventional starches are used as binders, then water retention is improved, but Brookfield viscosity becomes excessively high affecting transport and handling
Solution Approach 1:
The patent utilizes the specific parameter combination of high molecular weight (600,000-2,500,000 Da) and high amylopectin content (>95%) to achieve a unique rheological profile. This results in unexpectedly low Brookfield viscosity despite high water retention capacity, resolving the contradiction between water retention and handling ease.
3Reliability
If dextrin with high molecular weight is used to improve stability, then adhesive stability is improved, but viscosity at low shear becomes too high
Solution Approach 1:
The patent exploits the dynamic rheological behavior of high amylopectin dextrin, which exhibits shear-thinning characteristics. The viscosity adapts dynamically to shear conditions: maintaining stability at rest (low shear) while becoming sufficiently fluid under coating shear (high shear) for efficient application. This dynamic response resolves the contradiction between stability and productivity.
4Reliability
If natural binders are used to replace synthetic latexes, then environmental compatibility is improved, but control over rheological behavior at high shear gradient becomes difficult
Solution Approach 1:
The patent achieves precise rheological control through carefully selected parameters: molecular weight (600,000-2,500,000 Da) and amylopectin content (>95%). These parameter specifications enable predictable and controllable shear-thinning behavior, providing the necessary adaptability for coating applications while maintaining natural origin environmental compatibility.
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 high amylopectin dextrin-based coating colors exhibit stability comparable to commercial starches, improved rheological behavior under high shear, and enhanced water retention, significantly surpassing prior art performance levels.
Implementation Method 1
A sudden or strong increase in the viscosity (or 'drop-off', if the curve relative to the viscosity as a function of the temperature is considered) is characteristic of the 'retrogradation' of the starch. This phenomenon denotes the tendency which amylose macromolecules have to reassociate with one another during the cooling of the adhesive by formation of hydrogen bonds.
Implementation Method 2
providing a good compromise between water retention and rheological behavior at high shear gradient
Data Source
AI summary
Coating colors having a dextrin having high amylopectin content. When such a dextrin is used in the form of an adhesive, it confers an excellent stability on the adhesive. When the adhesive is subsequently incorporated in the coating color, it makes it possible to adjust the Brookfield viscosity thereof, while providing a good compromise between water retention and rheological behavior at high shear gradient. Also, the use of such dextrin for the manufacture of a coating color. Further, a process for the manufacture of a paper or of a cardboard coated on at least one its face with a coating color, and papers and cardboards thus obtained.