Cellulose Ether HASE Coating for Gypsum Mortar Workability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gypsum smoothing mortars and joint filler compositions face issues with lump formation due to fine gypsum particle sizes, leading to poor workability, and existing methods using cellulose ether and polyacrylamide combinations fail to adequately address this problem, requiring costly equipment and resulting in inconsistent performance.
Innovation Solution
A method involving kneading a wet cellulose ether mixture with a hydrophobic alkali swellable emulsion (HASE) polymer at elevated temperatures, followed by drying and grinding to achieve improved workability, where the cellulose ether is coated with the HASE polymer, reducing lump formation and enhancing the composition's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyacrylamide is blended with cellulose ether in powder form to improve workability, then the workability of gypsum smoothing mortar is improved, but the process becomes time-consuming and requires costly equipment
Solution Approach 1:
The patent combines polyacrylamide and cellulose ether into a single pre-blended powder composition, eliminating the need for separate blending equipment and operations. This merged additive composition maintains the workability benefits of polyacrylamide while removing the complexity of blending two separate powders.
Solution Approach 2:
The additive composition is prepared in advance with polyacrylamide and cellulose ether already mixed together in the correct proportions. This preliminary blending action is performed during manufacturing, so that during actual use, the user simply needs to add the pre-mixed composition to the gypsum mortar without requiring any additional blending equipment.
2Ease of operation
If polyacrylamide is blended with cellulose ether to improve workability, then the performance is enhanced, but dosage errors occur resulting in inconsistent performance
Solution Approach 1:
By merging polyacrylamide and cellulose ether into a single homogeneous powder composition with fixed ratios, the patent eliminates dosage errors that occur when users separately measure and mix two different powders. The pre-combined composition ensures consistent performance through uniform distribution of both components.
Solution Approach 2:
The additive composition is formulated as a homogeneous mixture where polyacrylamide and cellulose ether are uniformly distributed throughout the powder. This homogeneity ensures that every portion of the additive contains the correct proportion of both components, eliminating variability and ensuring consistent performance across different batches and applications.
3Shape
If gypsum particle size is reduced to improve smoothness, then the surface quality is enhanced, but lump formation increases leading to poor workability
Solution Approach 1:
The patent uses a composite additive composition containing both polyacrylamide and cellulose ether that works synergistically to address the lump formation issue. The combination of these two polymers creates a more effective anti-lumping system than either component alone, enabling the use of fine gypsum particles without the workability problems that would normally result.
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 significantly improves the workability of gypsum mortars by preventing lump formation and maintaining performance without the drawbacks of polymeric colloidal stabilizers, resulting in a more efficient and cost-effective additive composition.
Implementation Method 1
The cellulose ether becomes coated with the HASE polymer
Implementation Method 2
hydrophobic alkali swellable emulsion (HASE) polymer additive
Implementation Method 3
kneading at an elevated temperature of from 50 to 120 °C or, preferably, from 60 to 90 °C, a wet cellulose ether mixture
Implementation Method 4
drying and grinding the additive to an average particle size of at least 50 wt.%
Data Source
AI summary
The present invention provides additives for dry mix or tape joint compound compositions comprising one or more cellulose ether powders containing on its surface one or more hydrophobic alkali swellable emulsion polymer (HASE), preferably, one that is not crosslinked or which comprises, in copolymerized form, no multi-ethylenically unsaturated monomer, and, optionally, an inorganic basic filler. The present invention also provides methods to make the additive comprising kneading at from 50 to 120°C a wet cellulose ether mixture containing from 50 to 80 wt.% of water with from 0.5 to 25 wt.%, based on total cellulose ether solids, of the hydrophobic alkali swellable emulsion polymer; if desired, adding an inorganic basic filler, and drying and grinding. The additive can be combined with 0.1 to 20 wt.%, based on total cellulose ether solids, of a dry polyacrylamide.