Reactive Emulsifiers for Epoxy Resin Waterborne Stability
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Solution Overview
Problem
Epoxy resin emulsions in water lack effective, self-integrating emulsifiers that maintain stability and do not require organic solvents, leading to issues with storage and freeze/thaw stability.
Innovation Solution
Development of reactive emulsifiers formed by reacting polyols with propylene oxide and epichlorohydrin, followed by reaction with ethylene oxide, to create compounds that emulsify epoxy resins in water and integrate into the polymer during curing, along with mixtures of these emulsifiers for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive emulsifiers are used that become part of the cured coating, then the emulsifiers integrate into the polymer structure, but the storage stability and freeze/thaw stability are insufficient
Solution Approach 1:
The patent modifies the molecular structure of reactive emulsifiers by controlling the degree of polymerization and functional group composition. Specifically, the emulsifiers are designed with epoxy equivalent weights and hydroxyl numbers within specific ranges, and the ratio of ethylene oxide to propylene oxide units is optimized. These parameter changes enable the emulsifiers to maintain both reactivity for polymer integration and stability for long-term storage and freeze/thaw resistance
Solution Approach 2:
The invention creates composite emulsifier molecules that combine multiple functional groups (epoxide, hydroxyl, and polyether chains) in a single molecular structure. This composite approach allows the emulsifier to simultaneously provide reactivity with the epoxy resin, emulsification capability, and stability against degradation during storage and freeze/thaw cycles
2Reliability
If external emulsifiers are used for stabilization, then the emulsions can be prepared, but the emulsifiers do not become part of the coating and cannot diffuse out
Solution Approach 1:
The reactive emulsifiers are designed to automatically integrate into the cured coating through their epoxide groups that react with curing agents. This self-service mechanism eliminates the need for separate emulsifier removal steps and ensures complete incorporation into the polymer matrix, preventing any harmful residues from remaining in the final coating
3Ease of operation
If organic solvents are added to improve film formation, then the application properties are enhanced, but the storage stability and environmental compatibility deteriorate
Solution Approach 1:
The patent removes organic solvents from the epoxy resin emulsion system entirely. Instead, it uses water as the continuous phase and relies on the reactive emulsifiers to provide all necessary stabilization and film formation properties. This extraction of harmful solvents while maintaining functionality is achieved through the specific design of the reactive emulsifier molecules that can stabilize the emulsion without requiring organic additives
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 emulsifiers provide stable aqueous epoxy resin emulsions with long-term storage and freeze/thaw stability, ensuring no significant particle size change or sedimentation, and can withstand multiple freeze/thaw cycles.
Implementation Method 1
aqueous systems which comprise emulsified or dispersed epoxy resins
Implementation Method 2
Most of the emulsifiers used in this case possess epoxide groups and therefore become part of the cured coating
Implementation Method 3
these emulsifiers should not only be capable of emulsifying or dispersing epoxy resins in aqueous systems but should also themselves become part of the polymer formed in the course of the curing of the system
Data Source
AI summary
Disclosed is a process for the preparation of emulsifiers E1 which are obtained by (a) reacting a polyol with propylene oxide or a mixture of ethylene oxide and propylene oxide, to give an intermediate Z1, (b) reacting the intermediate Z1 with epichlorohydrin, forming an intermediate Z2, (c) reacting the intermediate Z2 with an adduct of ethylene oxide or a mixture of ethylene oxide and propylene oxide, with a C1-C22 monoalcohol, provided that on average at least one epoxide function of the intermediate Z2 is reacted and on average at least one epoxide function originating from the intermediate Z2 is retained. Compounds E1 are suitable as emulsifiers for preparing aqueous emulsions or dispersions of epoxy resins.