Stable Aqueous Wax Dispersion Using Alkali-Swellable Polymers
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Solution Overview
Problem
Existing aqueous polyolefin wax dispersions face limitations in achieving stable particle sizes above 1 μm and high wax content, with previous methods struggling to maintain stability and achieve particle sizes up to 100 μm, and solids content beyond 35% by weight.
Innovation Solution
The development of a stable aqueous micronized wax dispersion using a specific combination of micronized wax, alkali swellable acrylic acid emulsion, hydrophobically modified alkali swellable emulsion, hydrophobically modified ethoxylated urethane, and other additives, allowing for particle sizes between 1 to 100 μm and solids content up to 65% by weight, achieved by simply stirring the micronized wax with a dispersing agent at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If secondary dispersions are prepared by dispersing micronized wax with conventional dispersant systems, then particle size can be increased beyond 0.25 μm, but stable particle sizes above 1 μm cannot be maintained due to phase separation
Solution Approach 1:
The patent introduces a specific dispersant system comprising alkali-swellable emulsion polymers (containing carboxyl, carboxylate, or hydroxyl groups) as intermediary substances that mediate between the hydrophobic micronized wax particles and the aqueous phase. These dispersants adsorb onto the wax particle surfaces and provide steric and electrostatic stabilization, enabling stable dispersions with mean particle sizes of 1-100 μm without phase separation.
Solution Approach 2:
The patent changes the chemical and physical parameters of the dispersant system by using alkali-swellable emulsion polymers with specific functional groups (carboxyl, carboxylate, hydroxyl) and controlled molecular weights (10,000-1,000,000). The dispersant concentration is optimized at 0.1-10% by weight relative to wax content, and the pH is controlled at 7-12 to ensure proper swelling and stabilization of the dispersant polymers in the aqueous phase.
2Quantity of substance
If conventional dispersant systems are used to increase wax content, then solids content can be increased beyond 35% by weight, but achieving higher wax contents is difficult and requires complex assistant systems
Solution Approach 1:
The alkali-swellable emulsion polymer dispersants perform multiple functions simultaneously: they act as dispersing agents to prevent particle aggregation, as thickening agents to control rheology, and as stabilizing agents to maintain dispersion stability. This multi-functionality allows the patent to achieve high wax contents (5-65% by weight) with a relatively simple single-component dispersant system rather than complex multi-component assistant systems.
3Volume of moving object
If large particle sizes (1-100 μm) are achieved in wax dispersions, then the dispersions become unstable and undergo phase separation due to low density and hydrophobic nature of polyolefin wax
Solution Approach 1:
The patent creates a composite dispersion system where micronized polyolefin wax particles (hydrophobic, low density) are combined with alkali-swellable emulsion polymer dispersants (amphiphilic character) in an aqueous medium. The dispersant forms a protective interface layer around the hydrophobic wax particles, creating a stable composite structure that prevents phase separation despite the large particle size range of 1-100 μm and the inherent hydrophobicity of the polyolefin wax.
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
This approach enables the creation of stable, pourable, and stirrable wax dispersions with viscosities suitable for applications in leather treatment and surface defect filling, offering improved print retention and high-temperature release properties compared to standard systems.
Implementation Method 1
alkali swellable acrylic acid emulsion (ASE), hydrophobically modified alkali swellable emulsion (HASE)
Implementation Method 2
stable aqueous micronized wax dispersion which comprise from 5 to 65% by weight of micronized wax
Implementation Method 3
a surface active/dispersant agent
Implementation Method 4
thickening agent/dispersant
Data Source
AI summary
This invention relates to a stable aqueous wax dispersion comprisingA) from 5 to 65% by weight of micronized wax, the wax comprising an amide wax, polyethylene wax, modified polyethylene wax, polyethylene/amide wax, polyethylene/polytetrafluroethylene (PTFE) wax, polypropylene wax, modified polypropylene wax, polyethylene/polypropylene wax, polytetrafluroethylene (PTFE) wax or copolymers thereof or any mixture thereof having a mean particle size of from 1 to 100 μm and an acid number of less then 10 mg of KOH/g of wax andB) 0.5 to 20% by weight of a thickening/dispersing agent, comprising of a alkali swellable acrylic polymers (ASE) or a hydrophobically modified alkali swellable emulsion (HASE) or a hydrophobically modified ethoxylated urethane (HEUR) or a polymer containing both a high molecular weight acrylic copolymer moiety and a hydrophobically modified ethoxylated urethane as a thickening/dispersing agent or mixtures thereofC) 0 to 5% by weight of a water soluble base as a neutralizing agentD) 0 to 5% by weight of a surface active/dispersant agentE) 0 to 40% by weight of a polymeric binder or polymeric bindersF) 0 to 5% by weight smectic clay thickening agent(s).