Modified Cellulose Ether Binder for Ceramic Extrusion
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Solution Overview
Problem
Ceramic extrusion molding compositions using alkyl celluloses and hydroxyalkyl alkyl celluloses face issues with shape retention during drying due to gel formation, which slows down drying and increases extrusion pressure, leading to sticking and reduced molding rates.
Innovation Solution
A non-crosslinked, nonionic, water-soluble cellulose ether with hydroxyl groups substituted by alkyl halides or monoepoxides/monoisocyanates, providing a syneresis value of at least 25% by weight, which allows for thermal gelation with lower viscosity under high shear rates, enabling efficient extrusion molding and fast drying without shape distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If alkyl celluloses or hydroxyalkyl alkyl celluloses are used as binders to maintain shape during drying, then shape retention is improved, but drying rate deteriorates due to water trapped within gel
Solution Approach 1:
The patent changes the chemical structure of cellulose ether by introducing specific substituents (halides, monoepoxides, or monoisocyanates with 6-26 carbon atoms) and controlling the syneresis value (25-70% by weight). This parameter modification allows the binder to achieve thermal gelation for shape retention while enabling faster water evaporation during drying, thus resolving the contradiction between shape retention and drying rate.
2Stability of the object's composition
If binder is added in sufficient amount to develop thermal gel strength, then shape retention during drying is improved, but extrusion pressure increases due to high viscosity
Solution Approach 1:
The patent modifies the binder's physical-chemical parameters by selecting specific substituents (halides, monoepoxides, monoisocyanates) and controlling the syneresis value range (25-70%). This enables the binder to achieve sufficient thermal gel strength for shape retention while maintaining lower viscosity during extrusion, thus reducing extrusion pressure and allowing efficient molding at higher rates.
3Productivity
If extrusion molding rate is increased to improve productivity, then molding efficiency is improved, but shape retention deteriorates due to insufficient binding
Solution Approach 1:
The patent changes the binder's molecular structure by introducing specific substituents (halides, monoepoxides, monoisocyanates with 6-26 carbon atoms) and controlling syneresis value (25-70% by weight). This enables the binder to maintain sufficient binding strength and shape retention even at increased extrusion molding rates, thus resolving the contradiction between productivity and shape retention.
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 cellulose ether ensures effective shape retention and fast drying of ceramic parts during extrusion and drying processes, reducing extrusion pressure and maintaining part integrity even at increased molding rates.
Implementation Method 1
the binder displays thermal gelation in aqueous solution form
Implementation Method 2
the viscosity at a high shear rate during extrusion molding is extremely lower than the viscosity under no shearing conditions
Implementation Method 3
This interferes with evaporation of water and retards drying
Data Source
AI summary
A non-crosslinked, nonionic, water-soluble cellulose ether having a syneresis value of at least 25% by weight in which the hydrogen atom of a hydroxyl group is substituted by a C6-C26 alkyl halide, monoepoxide or monoisocyanate is useful as a binder in ceramic extrusion molding.