Linear Polycarboxylate Dispersants for Gypsum Slurry Flowability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current gypsum-containing products face challenges in achieving sufficient strength due to excess water usage, which increases production costs and reduces product density, and existing dispersants like polynaphthalene sulfonates and branched polycarboxylates have limitations in efficacy and compatibility.

Innovation Solution

The use of linear polycarboxylate dispersants, composed of specific monomeric repeating units, reduces water demand and enhances the strength of gypsum products by improving dispersion and reducing air entrapment, allowing for lower dispersant dosages while maintaining flowability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If excess water is added to form gypsum slurry, then flowability is improved, but product strength decreases and production cost increases

Engineering Contradiction:

ImproveflowabilityVSAvoidproduct strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent changes the chemical composition parameter by introducing linear polycarboxylate dispersant with specific molecular weight (5,000-50,000) and structure (absence of side chains), which fundamentally alters the water-gypsum interaction mechanism. This enables reduced water content while maintaining flowability, directly resolving the contradiction between flowability and strength.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system combining linear polycarboxylate dispersant with calcium sulfate hemihydrate and water. The dispersant acts as a bridging component that enhances particle separation and lubrication, allowing the slurry to achieve optimal flowability at lower water-cement ratios, thereby maintaining both flowability and strength.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If excess water is added to form gypsum slurry, then flowability is improved, but production cost increases due to evaporation requirements

Engineering Contradiction:

ImproveflowabilityVSAvoidevaporation energy

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

By changing the dispersant parameter to linear polycarboxylate with optimized molecular weight and structure, the patent reduces the water demand for achieving proper slurry flowability. This directly reduces the amount of excess water that would otherwise need to be evaporated, lowering energy consumption and production costs.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If polynaphthalene sulfonate or branched polycarboxylate dispersants are used, then water reduction is achieved, but compatibility and efficacy are limited

Engineering Contradiction:

Improvewater contentVSAvoidcompatibility

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent changes the dispersant structure parameter from branched to linear configuration, and optimizes molecular weight to 5,000-50,000 range. This structural parameter change improves compatibility with various gypsum sources including high clay stucco, while maintaining effective water reduction capability, thus resolving the contradiction between water reduction and adaptability.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If dispersant dosage is increased, then flowability is improved, but production cost increases

Engineering Contradiction:

ImproveflowabilityVSAvoidproduction cost

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

By optimizing the dispersant molecular weight to 5,000-50,000 and using linear structure, the patent enhances the dispersant's efficiency. This allows achieving optimal flowability at lower dosages compared to conventional dispersants, directly reducing material costs while maintaining performance.

Inventive Principle:

Principle #35Parameter changes

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

Linear polycarboxylate dispersants effectively reduce water content, enhance strength, and improve the dispersion of high clay stucco sources, offering a cost-effective solution by minimizing the need for expensive branched polycarboxylates and polynaphthalene sulfonates, while maintaining the flowability of gypsum slurries.

Implementation Method 1

Linear polycarboxylate dispersants effectively reduce water content, enhance strength, and improve the dispersion of high clay stucco sources

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

calcium sulfate hemihydrate reacts with a sufficient amount of the water to convert the hemihydrate into a matrix of interlocking calcium sulfate dihydrate crystals

Methodology Applied

Scientific EffectHydration: Mineral Hydration

Data Source

PatentUS10968138B2Gypsum slurries with linear polycarboxylate dispersants

Publication Date: 2021.04.06 UNITED STATES GYPSUM CO

AI summary

A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.