Spray Drying Polymer Dispersant Polysaccharide Mortar Additive
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Solution Overview
Problem
Existing dry mortar mixtures face issues with segregation and inhomogeneous distribution of additives due to differences in specific density, grain size, and surface properties, leading to variations in quality and mechanical strength, and the conversion of polysaccharide-based rheology additives into powder form is complex and costly.
Innovation Solution
A method involving the preparation of a powdery composition containing polymeric dispersants with anionic and/or anionogenic groups and polyether side chains, combined with polysaccharides, using an aqueous dispersion with controlled viscosity for spray drying, which results in a rheological additive that prevents segregation and enhances flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polysaccharide-based rheology additives are converted into powder form through traditional methods, then the powder can be used in dry mortar mixes, but the process becomes complex and costly with poor flowability
Solution Approach 1:
The patent combines polymeric dispersants and polysaccharides into a single aqueous dispersion before spray drying, creating a unified powdered composition that integrates multiple functions (dispersion and rheology control) into one additive package, simplifying the manufacturing process while maintaining powder flowability
Solution Approach 2:
The patent changes the physical and chemical parameters of the polysaccharide by combining it with polymeric dispersants in specific weight ratios (1:4 to 1:20), which modifies the dispersion properties and enables successful spray drying without compromising the rheological functionality of the polysaccharide
2Ease of operation
If dispersants are added to aqueous slurries to improve workability, then flowability and sprayability improve, but excess dispersant causes water bleeding and segregation
Solution Approach 1:
The patent creates a homogeneous powdered composition by co-drying polymeric dispersants and polysaccharides together in an aqueous dispersion, ensuring uniform distribution of both components in the final powder, which prevents localized excess concentrations that would cause water bleeding and segregation
Solution Approach 2:
The aqueous dispersion serves as an intermediary medium that allows both polymeric dispersants and polysaccharides to be combined in a controlled manner, enabling precise dosage control and uniform distribution in the final dry mortar mix, preventing the harmful effects of excess dispersant
3Strength
If packing density is adjusted to reduce voids in mortar, then mechanical strength improves, but grain sizes must be extremely well matched which is difficult to achieve
Solution Approach 1:
The patent extracts the function of void reduction from the physical packing of grains and transfers it to the chemical-rheological domain by using the powdered composition (combining dispersants and polysaccharides) to control water distribution and reduce free water content, allowing normal grain size variations 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 method produces high-quality, segregation-proof dry mortar mixtures with improved flowability and mechanical strength, reducing the need for grinding steps and optimizing the use of polysaccharides, thus enhancing industrial scalability and cost-effectiveness.
Implementation Method 1
b) spray-drying the aqueous dispersion prepared in process step a)
Data Source
AI summary
The invention relates to a method for producing a powdery composition containing at least one polymer dispersant (PD), which comprises structural units having anionic and/or anionogenic groups and structural units having polyether side chains, and at least one polysaccharide (PS). The method comprises the following steps: a) producing an aqueous dispersion, the viscosity of the dispersion being less than 10,000 mPa, containing the at least one polymer dispersant (PD) and the at least one polysaccharide (PS), and b) spray-drying the aqueous dispersion produced in method step a). The invention further relates to the use of the powdery composition according to the invention in inorganic binder compositions, in particular as a rheological additive.