Hydroxamic Acid Polymer Dispersant for High-Solid Inorganic Slurries

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Solution Overview

Problem

Conventional dispersants for inorganic particle compositions, particularly those containing clay mineral impurities, exhibit low dosage efficiency and retard the crystallization of calcium sulfate dihydrate, leading to adverse effects in applications like gypsum wallboard production, and fail to achieve high solid aqueous slurries with acceptable viscosity and stability.

Innovation Solution

A water-soluble polymer with a carbon chain and polyether side chains featuring hydroxamic acid groups or their salts, which provides high dosage efficiency and reduces viscosity in inorganic binder and pigment compositions, even with clay mineral impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dispersants (polyelectrolytes like polycarboxylate ethers) are used to disperse inorganic particles, then electrostatic and steric dispersing mechanisms are achieved, but dosage efficiency is low and crystallization of calcium sulfate dihydrate is retarded

Engineering Contradiction:

Improvedispersing actionVSAvoiddosage efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the chemical parameter of the dispersant by introducing hydroxamic acid groups instead of conventional carboxylate groups. This chemical modification enables the dispersant to maintain effective dispersing action while reducing the dosage required, thereby resolving the contradiction between reliability of dispersing action and productivity in terms of dosage efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure combining a polyether backbone with hydroxamic acid functional groups. This composite structure integrates the electrostatic dispersing capability of charged groups with the steric hindrance provided by polyether chains, achieving high dispersing efficiency at low dosages without retarding calcium sulfate dihydrate crystallization

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If clay mineral impurities are present in gypsum sources, then natural gypsum availability is improved, but dispersant dosage efficiency is reduced and adverse effects occur

Engineering Contradiction:

Improvegypsum availabilityVSAvoiddispersant performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by designing a dispersant with specific functional groups (hydroxamic acid) that selectively interact with clay mineral surfaces. The hydroxamic acid groups have particular affinity for metal oxides and hydroxides in clay, providing localized effective dispersing action at the clay-gypsum interface while maintaining overall system performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The hydroxamic acid groups act as intermediaries that bridge the polyether backbone and the clay mineral surfaces. These functional groups specifically adsorb onto clay particles, mediating the interaction between the dispersant and impurities, thereby preventing the adverse effects that clay minerals would otherwise have on dispersant performance

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If high solid aqueous slurries are prepared, then inorganic particle composition concentration is increased, but viscosity becomes unacceptably high and stability is reduced

Engineering Contradiction:

Improveslurry concentrationVSAvoidslurry stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameter of the dispersant structure to include hydroxamic acid groups with specific binding characteristics. This modification enables the dispersant to effectively stabilize high concentration slurries by strongly adsorbing onto particle surfaces, preventing aggregation, and maintaining slurry stability even at high solid contents where conventional dispersants would fail

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

The polymer achieves high solid aqueous slurries with reduced viscosity and improved stability, enhancing the performance of inorganic binder and pigment compositions.

Implementation Method 1

The polymers are adsorbed via their anionic groups onto the positively charged regions of the particles

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

electrostatic dispersing mechanism

Methodology Applied

Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 3

the side chains project into the pore space filled with mixing water and in this way inhibit, by steric hindrance, agglomeration of the solid particles

Methodology Applied

Scientific EffectSteric hindrance:

Data Source

PatentUS20260008880A1Water-soluble polymer comprising hydroxamic acid groups

Publication Date: 2026.01.08 BASF SE

AI summary

The invention relates to a water-soluble polymer comprising a main chain which consists of a carbon chain with at least 16 carbon atoms and polyether side chains, wherein hydroxamic acid groups or their salts are attached to the main chain. Further disclosed is an inorganic particle composition comprising the water-soluble polymer. A further aspect of the present invention is the use of the water-soluble polymer of the invention as dispersant in inorganic particle compositions.