Cellulose Ether Liquid Defoamer Compound for Cement Mortar Open Time
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Solution Overview
Problem
Cement-based tile adhesives and thermal insulation composite systems face issues with short open times due to skin formation, leading to inadequate wetting and processing difficulties, as existing defoamers either fail to provide a temporary defoaming effect or increase mortar density, making them harder to process.
Innovation Solution
Incorporating a liquid defoamer, specifically fatty acid esters or fatty alcohol alkoxylates, into a water-soluble cellulose ether to create a compound that extends open time and improves wetting while maintaining processing ease, without the need for natural biopolymers or quaternary ammonium compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If liquid defoamers are incorporated into cement-based mortars, then open time is extended and skin formation is reduced, but existing defoamers increase mortar density making them harder to process
Solution Approach 1:
The patent changes the physical-chemical parameters of the defoamer by selecting specific liquid defoamers (fatty acid esters or fatty alcohol alkoxylates) with appropriate molecular structures and properties. These parameter changes enable the defoamer to reduce surface tension and prevent skin formation without significantly increasing mortar density, thus extending open time while maintaining processing ease.
Solution Approach 2:
The patent creates a composite system by combining liquid defoamers with water-soluble cellulose ethers in specific concentrations. This composite approach synergistically enhances the defoaming effect and water retention properties, extending open time without compromising workability or increasing density to problematic levels.
2Duration of action of moving object
If skin formation occurs on the mortar surface, then processing time is limited, but preventing skin formation requires additives that may increase density
Solution Approach 1:
The patent modifies the surface properties of the mortar by incorporating liquid defoamers that change the surface tension parameters. This prevents premature skin formation by maintaining adequate surface wetting and fluidity throughout the processing time, without requiring high-density additive packages.
Solution Approach 2:
The patent uses water-soluble cellulose ethers as a base material that replicates and enhances the water-retention properties naturally present in cement systems. This copying of beneficial water retention behavior extends processing time without needing additional dense chemical additives.
3Strength
If conventional defoamers are used to reduce air voids, then strength may improve, but they fail to provide temporary defoaming effect needed for extended processing
Solution Approach 1:
The patent employs dynamic defoaming action where liquid defoamers are released progressively during mixing and application. This dynamic approach provides initial vigorous defoaming to reduce air voids for strength, followed by sustained surface protection that prevents skin formation and extends processing time, unlike static conventional defoamers.
Solution Approach 2:
The patent ensures continuous useful action by selecting liquid defoamers that maintain their defoaming and surface-protection functions throughout the entire processing window. The fatty acid esters or fatty alcohol alkoxylates continue to prevent skin formation from mixing through application, providing uninterrupted beneficial action that extends processing time while maintaining strength.
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 cellulose ether with a liquid defoamer significantly enhances the open time and wetting of cement tile adhesives and ETICS plasters, improving tensile adhesive strengths and maintaining ease of processing, as demonstrated by increased wetting percentages and adhesive tensile strength over various storage conditions.
Implementation Method 1
water-soluble cellulose ethers into which one or more liquid defoamers are incorporated
Implementation Method 2
improving the wettability of cement-based mortars
Data Source
Figure 1~2
AI summary
This document describes the use of a compound consisting of cellulose ether and one or more liquid defoamers. It is preferably used as a modified cellulose ether in dry mortars to extend the open time.