Self-Binding Pigment Suspension via Supercritical CO2 Extraction
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Solution Overview
Problem
Self-binding pigment particle suspensions often result in paper coatings with worsened mechanical and optical properties due to high amounts of free dissolved binder, which is detrimental for applications in paper coatings, paints, and plastics.
Innovation Solution
A process involving the use of anionic and/or amphoteric starch is introduced, where the starch is mixed with an aqueous pigment material suspension and ground to reduce the amount of free starch, resulting in improved mechanical and optical properties of the paper coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If self-binding pigment particle suspensions are used in paper coatings, then the binder provides necessary adhesion and cohesion, but the high amounts of free dissolved binder worsen mechanical and optical properties
Solution Approach 1:
The patent extracts the harmful free dissolved binder from the system by using supercritical carbon dioxide to remove excess binder from the pigment particle suspension, retaining only the binder that is intimately bound to the pigment particles, thereby eliminating the harmful effect while preserving the necessary adhesion and cohesion
Solution Approach 2:
The patent changes the physical state of carbon dioxide from supercritical fluid to gas by adjusting pressure and temperature parameters, enabling the selective removal of free dissolved binder through phase change, which resolves the contradiction between maintaining binder functionality and eliminating harmful effects
2Ease of operation
If mineral materials and binders are handled separately, then logistics and storage are simplified, but physical and chemical interactions in comparable mixtures cause unwanted effects
Solution Approach 1:
The patent merges mineral materials and binder into intimate pigment-binder aggregates during the grinding process, creating self-binding pigment particles that combine both components into a single functional unit, thereby preventing unwanted interactions while maintaining ease of handling as a unified material
Solution Approach 2:
The patent creates composite self-binding pigment particles where mineral material and binder are intimately combined at the micro level, forming a new composite material that exhibits both the properties of mineral fillers and the adhesive properties of binders, eliminating separation logistics while preventing harmful interactions
3Strength
If grinding is used to reduce particle size of mineral materials, then mechanical properties improve, but the process complexity and energy consumption increase
Solution Approach 1:
The patent uses supercritical carbon dioxide to perform multiple functions simultaneously: it acts as a grinding medium to reduce particle size, as a binder carrier to distribute binder uniformly, and as a cleaning agent to remove free dissolved binder, thereby achieving mechanical stability improvement without increasing process complexity
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 process leads to self-binding pigment particle suspensions with enhanced mechanical and optical properties, reducing the content of free dissolved binder and improving the performance of paper coatings.
Implementation Method 1
the pigment material surface charge after step d) is neutral or anionic
Implementation Method 2
combining the aqueous pigment material particles and starch of step c) by grinding
Data Source
AI summary
The invention relates to a process for preparing self-binding pigment particle suspensions, to a self-binding pigment particle suspension as well as to a paper product comprising self-binding pigment particles and to the use of the self-binding pigment particle suspension in paper applications, such as in paper coating or as filler material.