Ester-Based Concrete Surface Retarder for Neutral pH Etching
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Solution Overview
Problem
Existing surface retarders for concrete surfaces are acidic, leading to corrosive effects and irritating fogs during spray application, while also failing to provide clear etches effectively.
Innovation Solution
A surface retarder composition comprising oil/solvent-soluble or oil-dispersible alkyl-ester-of-hydroxycarboxy compounds, such as alkyl esters of citric acid and tartaric acid, distributed within a continuous non-aqueous carrier phase, which is spray-applicable and can be used to retard the curing of concrete surfaces, allowing for pH neutrality and enhanced etching capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid-based surface retarders are used, then etching capability is achieved, but corrosive effects and irritating fogs occur due to acidity
Solution Approach 1:
The invention changes the chemical parameter of the retarder from acidic to neutral pH by using esters of hydroxycarboxylic acids instead of free acids. This parameter change maintains etching capability while eliminating corrosive effects and irritating fogs associated with acid-based retarders.
Solution Approach 2:
The invention uses composite material systems combining esters of hydroxycarboxylic acids with vegetable oil derivatives as carriers. This composite approach provides both the neutral pH benefit and the desired etching performance through the synergistic interaction of the ester active ingredient and the oil carrier system.
2Object-affected harmful factors
If solid powder retarder is used, then pH neutrality is achieved, but incorporation into spray carrier is difficult without grinding
Solution Approach 1:
The invention changes the physical state parameter of the retarder from solid powder to liquid ester form. This parameter change enables direct incorporation into spray carriers without requiring time-consuming grinding steps, while maintaining the neutral pH advantage of ester-based compounds.
3Duration of action of moving object
If conventional acid-based retarders are used, then surface retardation is achieved, but clear etching is not obtained
Solution Approach 1:
The invention changes the chemical structure parameter from conventional acid-based retarders to esters of hydroxycarboxylic acids. This structural parameter change provides both the surface retardation function and the clear etching capability that was lacking in acid-based systems, as the ester groups enable controlled reaction with cement hydrates.
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 solution provides a less acidic pH level, easier incorporation of retarder particles, and enhanced retarding activity that achieves sharper etchings in concrete materials, reducing corrosive effects and improving the etching process.
Implementation Method 1
retarding of concrete surfaces... fresh concrete containing aggregates is poured and leveled, and then the retarder is sprayed as an aqueous solution onto the surface... to retard the curing thereof
Data Source
AI summary
Compositions and methods of the invention for retarding the surface of a concrete or other hydratable cementitious composition involve the use of at least one alkyl-ester-of-hydroxycarboxy compound contained in the form of particles or as a discontinuous phase distributed within a continuous non-aqueous carrier phase that is spray-applicable in liquid form. The set retarder helps to achieve lower pH and to avoid irritating fogs during spray application of the surface retarder when compared to prior art acid-containing surface retarders.