Emulsion Polymer Waterproofing Membrane Fast Curing Cement
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Solution Overview
Problem
Existing cementitious waterproofing membranes using fast-setting cements face challenges such as rapid thickening, short pot life, rigidity, and cracking, which limit their flexibility and effectiveness in providing sufficient crack bridging, especially in dry/wet conditions.
Innovation Solution
A two-component composition comprising an aqueous emulsion copolymer with a glass transition temperature of −40 to 0°C, including a reducing agent, and a fast curing dry mix powder of hydraulic cement and high alumina content cement, which maintains flexibility and pot life, allowing for the application of multiple layers within a day without cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast setting cement (CAC) is used to achieve faster curing, then curing speed is improved, but the wet mortar thickens very fast making applicability and workability difficult
Solution Approach 1:
The patent introduces an aqueous emulsion copolymer as an intermediary substance between the fast-setting cement and the application process. This polymer modifier acts as a working agent that controls the thickening rate, allowing the mortar to remain workable for a sufficient period while still achieving fast curing. The copolymer contains functional groups that interact with the cement hydration process, moderating the setting behavior without sacrificing the inherent speed advantage of CAC.
Solution Approach 2:
The patent modifies the chemical composition parameters of the cement-based system by incorporating specific copolymers with controlled glass transition temperatures (Tg from -40 to 0°C). By changing the polymer composition parameters - specifically using copolymers made from (meth)acrylic esters, vinyl aromatic monomers, and carboxylic acid monomers - the system achieves an optimal balance between workability duration and curing speed. The Tg range is carefully selected to provide flexibility during application while enabling rapid strength development.
2Loss of time
If fast setting cement is used to reduce curing time, then time to apply subsequent layers is reduced, but the resulting waterproofing membrane is too rigid and cracks
Solution Approach 1:
The patent carefully controls the glass transition temperature (Tg) parameter of the emulsion copolymer within the range of -40 to 0°C (preferably -20 to 0°C). This specific Tg range provides the optimal balance: low enough to ensure flexibility and crack bridging capability in the cured membrane, yet high enough to allow rapid curing. The copolymer composition is precisely formulated with 60-89.9 wt.% nonionic (meth)acrylic monomers, 10-40 wt.% vinyl aromatic monomers, and 0.1-2.0 wt.% carboxylic acid monomers to achieve these properties.
Solution Approach 2:
The patent creates a composite waterproofing membrane system combining fast-setting calcium alumina cement with specially designed aqueous emulsion copolymers. This composite approach allows the cement matrix to provide rapid strength gain and structural integrity, while the copolymer phase provides flexibility, elongation, and crack bridging. The synergistic combination enables the membrane to cure quickly while maintaining the flexibility needed to accommodate substrate movements and prevent cracking.
3Strength
If the glass transition temperature of the emulsion polymer is reduced to increase flexibility, then crack bridging is improved, but the polymer to cement ratio must be increased significantly
Solution Approach 1:
The patent optimizes the Tg parameter of the copolymer to a specific range (-40 to 0°C) that provides sufficient flexibility without requiring excessive polymer content. This optimized Tg range allows the system to achieve good crack bridging at practical polymer-to-cement ratios. The copolymer structure is designed with appropriate side chain lengths and functional groups that provide flexibility at lower polymer concentrations compared to polymers with much lower Tg values.
Solution Approach 2:
The patent enhances the local quality of the waterproofing membrane by incorporating the copolymer at strategic locations within the cement matrix. The copolymer concentrates at the cement-polymer interface and forms a flexible network that locally provides crack bridging where needed. This localized enhancement of flexibility allows the system to achieve good crack resistance without uniformly increasing the overall polymer content throughout the entire mixture.
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 composition achieves superior waterproofing performance with flexibility and crack bridging capabilities, enabling the membrane to elongate and move with mechanical stress, maintaining a waterproof surface while allowing for rapid application and curing without cracking.
Implementation Method 1
aqueous emulsion copolymer having a measured glass transition temperature (Tg) of from −40 to 0° C.
Implementation Method 2
comprising the residue of a reducing agent, preferably, an ascorbic acid
Implementation Method 3
a fast curing dry mix powder composition of a hydraulic cement and a high alumina content cement
Implementation Method 4
the aqueous emulsion copolymer is the copolymerization product of (i) from 60 to 89.9 wt. % of one or more nonionic (meth)acrylic monomers, (ii) from 10 to 40 wt. % of one or more vinyl aromatic monomers
Data Source
AI summary
The present invention provides two-component compositions comprising a component A) one or more acrylic aqueous emulsion copolymer having a measured glass transition temperature (Tg) of from −20 to 0° C. and which is the copolymerization product of (i) from 60 to 89.9 wt. % of one or more nonionic (meth)acrylic monomers, (ii) from 10 to 40 wt. % of one or more vinyl aromatic monomers, (iii) from 0.1 to 2.0 wt. % of one or more monomers chosen from itaconic acid, methacrylic acid, amides of a,β-unsaturated C3 to C6 carboxylic acids, and mixtures thereof, all wt. %s of monomers based on the total monomer solids, wherein the aqueous emulsion copolymer has at least one residue of an ascorbic acid reducing agent or is the copolymerization product of a monomer (iii) comprising itaconic acid, and, a separate component B) comprising a fast curing dry mix powder composition of a hydraulic cement and a high alumina content cement.