Epoxy-Polyester Binder Mixtures for Corrosion Resistance
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Solution Overview
Problem
Aqueous coating binders based on cationically stabilized epoxy amine adducts face challenges in providing effective corrosion resistance under high temperature and high humidity conditions, particularly exceeding 30 °C and 50% relative humidity.
Innovation Solution
The development of binder mixtures comprising chain-extended epoxy amine adducts combined with carboxy functional polyesters containing a limited amount of aromatic constituents, which are chain-extended and then dispersed in water, forming coatings without the need for additional curing agents, enhancing corrosion resistance and allowing use on substrates like metal, wood, and concrete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chain-extended epoxy amine adducts are used as aqueous coating binders, then adhesion and corrosion protection are achieved, but corrosion resistance under high temperature and high humidity conditions deteriorates
Solution Approach 1:
The patent combines chain-extended epoxy amine adducts with carboxy functional polyesters to create a composite binder system. This composite approach leverages the complementary properties of both components: the epoxy amine adduct provides adhesion and basic corrosion protection, while the carboxy functional polyester enhances thermal stability and corrosion resistance under harsh conditions, resolving the contradiction between achieving corrosion protection and maintaining performance at high temperatures.
Solution Approach 2:
The patent modifies the chemical parameters of the binder system by introducing carboxy functional polyesters with specific acid numbers (4-50 mg/g) and controlled aromatic content (1-15% by mass). These parameter changes in the binder composition enable the coating to maintain its protective properties under elevated temperature and humidity conditions while preserving the adhesion and corrosion protection benefits of the epoxy amine adduct system.
2Reliability
If conventional epoxy amine adducts are used, then coating formation is achieved, but corrosion resistance under tropical conditions deteriorates
Solution Approach 1:
The patent creates a composite binder system combining chain-extended epoxy amine adducts with carboxy functional polyesters. This composite formulation enhances the coating's resistance to humidity and tropical conditions by leveraging the hydrophobic properties and chemical stability of the polyester component, which complements the adhesion-promoting properties of the epoxy amine adduct, thereby resolving the contradiction between achieving corrosion protection and maintaining performance under high humidity.
Solution Approach 2:
The patent adjusts the chemical parameters of the binder by incorporating carboxy functional polyesters with controlled acid numbers (4-50 mg/g) and limited aromatic content (1-15% by mass). These parameter modifications enhance the coating's resistance to moisture penetration and chemical degradation under tropical conditions while preserving the essential adhesion and corrosion protection functions.
3Reliability
If additional curing agents are used to enhance corrosion resistance, then protection improves, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent employs a self-service approach where the carboxy functional polyester component inherently provides corrosion resistance and thermal stability without requiring additional curing agents. The binder system is designed to achieve its protective function through the intrinsic properties of the modified epoxy amine adduct-polyester combination, eliminating the need for separate curing agents and simplifying the manufacturing process while maintaining enhanced corrosion protection.
Solution Approach 2:
The patent modifies the binder composition by incorporating carboxy functional polyesters with specific acid numbers (4-50 mg/g), which inherently provide corrosion resistance and thermal stability. This parameter change in the binder formulation enables the coating to achieve enhanced protection without requiring additional curing agents, thereby reducing process complexity while improving corrosion resistance.
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 binder mixtures provide exceptional corrosion protection for metals and can be used as sealers for wood and concrete, demonstrating improved performance under tropical conditions without the use of additional crosslinkers, maintaining effectiveness at high temperatures and humidity levels.
Implementation Method 1
Such systems have been known from EP 1 207 187 B1. The corrosion resistance under high temperature and high humidity conditions (temperatures in excess of 30 °C, relative humidity in excess of 50 %) of such systems still needs to be improved.
Implementation Method 2
which exhibit excellent adhesion and impart good corrosion protection
Implementation Method 3
The corrosion resistance under high temperature and high humidity conditions (temperatures in excess of 30 °C, relative humidity in excess of 50 %) of such systems still needs to be improved
Implementation Method 4
carboxy functional polyesters B which contain a limited amount of aromatic constituents in mass fractions of from 1 % to 15 % and have an acid number of from 4 mg/g to 50 mg/g
Data Source
AI summary
This invention relates to binder mixtures comprising mass fractions of from 70 % to 98 % of chain-extended epoxy amine adducts A and from 2 % to 30 % of carboxy functional polyesters B that contain a limited amount of aromatic constituents in mass fractions of up to 15 % and have an acid number of from 4 mg/g to 50 mg/g, a method of making these binder mixtures, and a method of use thereof in coatings for metals, wood, cardboard, plaster, and concrete.