Epoxy Acrylate Dispersion Stability via HLB Control
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Solution Overview
Problem
Radiation-curable aqueous epoxy acrylate dispersions have poor storage stability and difficulty in dispersion due to the hydrophobic nature of epoxy acrylate resins, leading to unsatisfactory coating properties such as tackiness and phase separation.
Innovation Solution
A coordinated system of acrylated dispersants and epoxy acrylate resins is developed, where the phase inversion temperature is above 50°C, using nonionic compounds with specific HLB values and reaction stages to achieve stable dispersions suitable for various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If epoxy acrylate resins are dispersed in water using conventional surfactant mixtures, then dispersion is achieved, but storage stability deteriorates and material properties are compromised
Solution Approach 1:
The patent introduces a specific nonionic surfactant as an intermediary substance with carefully controlled HLB value (8-16) to mediate between the hydrophobic epoxy acrylate resin and water. This intermediary enables dispersion while maintaining storage stability, resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the HLB value of the surfactant within the range of 8-16, and limiting the surfactant concentration to 0.1-10 wt% based on resin content. These parameter optimizations enable stable dispersion without compromising storage stability, addressing both manufacture ease and reliability.
2Stability of the object's composition
If larger amounts of surfactant mixtures are used to disperse epoxy acrylate, then dispersion stability improves, but coating material properties deteriorate
Solution Approach 1:
The patent optimizes the surfactant concentration parameter by limiting it to 0.1-10 wt% of the resin content, which is significantly lower than conventional approaches. This parameter optimization achieves adequate dispersion stability while preventing harmful effects on coating properties such as adhesion, hardness, and flexibility.
Solution Approach 2:
The patent applies local quality by selecting a surfactant with specific HLB value range (8-16) that is locally optimized for epoxy acrylate resins. This targeted approach provides sufficient dispersion stability at low concentrations without the need for excessive surfactant that would harm material properties.
3Ease of manufacture
If epoxy acrylate dispersions are prepared by physical emulsification processes, then dispersion is achieved, but storage stability and phase separation resistance are insufficient
Solution Approach 1:
The patent uses a nonionic surfactant as an intermediary that remains physically present in the dispersion system to continuously stabilize the interface between hydrophobic resin and water. This mediator prevents phase separation during storage while maintaining the simplicity of physical emulsification processes.
Solution Approach 2:
The patent optimizes the HLB value parameter of the surfactant to the range of 8-16, which provides optimal balance between hydrophilic and hydrophobic characteristics. This parameter setting ensures long-term storage stability and phase separation resistance while keeping the manufacturing process simple.
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 resulting dispersions exhibit excellent thermal and chemical resistance, high hardness, and improved storage stability, with coatings becoming tack-free before radiation curing, ensuring problem-free processing and enhanced film formation.
Implementation Method 1
a dispersant (D*) with at least 1 acrylate group per molecule... dispersed in water
Implementation Method 2
radiation-curable aqueous epoxy acrylate dispersions... radiation curing
Data Source
AI summary
The invention relates to aqueous radiation-hardenable epoxy acrylate dispersions comprising (a) an epoxy acrylate resin (P*) with at least two acrylate groups per molecule, wherein at 25 degrees Celsius, said epoxy acrylate resin is not self-disperging in water; and (b) a dispergator (D*) with at least one acrylate group per molecule, wherein said dispersions can be produced by converting, in a first step (i), in the presence of a catalyst if need be, one or several compounds (A) selected from the group of non-ionic compounds having a HLB value of less than 12, and containing at least two oxirane groups per molecule, with one or several compounds (B) selected from the group of non-ionic compounds having a HLB value in the range from 12 to 20, and which contain at least one h-acid group (ZH) per molecule. The compounds (A) and (B) are employed at an equivalence ratio EpO (A) : ZH (B) in the range from 1.3:1 to 400:1, and in a second step (ii), the reactive mixture thus obtained is converted, in the presence of a catalyst if need be, with one or several non-ionic compounds having a HLB value of less than 12, and containing at least two oxirane groups per molecule (compounds A), and with one or several compounds (C) selected from the group of non-ionic compounds having a HLB value of less than 12, and which contain at least two H-acid groups. The compounds (A) and (C) are employed at an equivalence ratio EpO (A) : ZH (C) in the range from 1.1:1 to 20:1. In a third step (iii), the reactive mixture thus obtained is converted, in the presence of a catalyst if need be, with acrylic acid by ring opening of all epoxy groups. In a fourth step (iv), the reactive mixture thus obtained is disperged in water.