Addition Polymer Coating with Phosphorous Acid for Low-Temperature Curing
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Solution Overview
Problem
Existing electrodepositable coating compositions either lack stability to hydrolysis, leading to degradation upon water exposure, or require high heating temperatures for curing, which is undesirable.
Innovation Solution
An addition polymer with a backbone containing a phosphorous acid group covalently bonded via a carbon-carbon bond and at least one carbamate functional group, used in an aqueous dispersion for electrophoretic deposition, which cures at low temperatures and maintains hydrolytic stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing electrodepositable coating compositions are used to achieve hydrolytic stability, then the coating resists water degradation, but high heating temperatures are required for curing
Solution Approach 1:
The patent changes the chemical parameters of the coating composition by incorporating specific functional groups (carbamate and phosphorous acid) into the polymer structure. This chemical modification allows the coating to achieve hydrolytic stability through molecular design rather than high-temperature curing, thereby reducing the curing temperature requirement while maintaining reliability
Solution Approach 2:
The invention creates a composite functional structure within the polymer chain by combining carbamate groups (providing low-temperature curing capability) with phosphorous acid groups (providing hydrolytic stability). This composite approach at the molecular level enables both desired properties to coexist without requiring extreme curing conditions
2Temperature
If existing electrodepositable coating compositions are used to reduce curing temperature, then lower heating temperatures are required, but the coating lacks hydrolytic stability and degrades upon water exposure
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing phosphorous acid groups into the polymer structure. This parameter change enables the coating to maintain hydrolytic stability even at lower curing temperatures, reversing the traditional trade-off where low temperature curing compromised water resistance
Solution Approach 2:
The invention integrates multiple functional groups within the same polymer chain: carbamate groups enable low-temperature curing while phosphorous acid groups simultaneously provide hydrolytic stability. This molecular composite structure eliminates the need to choose between temperature reduction and stability maintenance
3Reliability
If conventional coating methods are used to achieve complete curing, then proper coating performance is obtained, but high energy consumption occurs due to high heating temperatures
Solution Approach 1:
The patent changes the chemical reactivity parameters of the coating system by incorporating functional groups that can undergo curing reactions at lower temperatures. This parameter modification maintains complete curing and proper coating performance while reducing the thermal energy input required, thereby lowering energy consumption
Solution Approach 2:
The invention utilizes chemical phase transitions at lower temperature ranges through the designed functional group reactions. The carbamate and phosphorous acid groups enable curing reactions to proceed efficiently at reduced temperatures, maintaining coating performance while reducing the thermal energy phase transition requirements
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 solution provides a coating that is hydrolytically stable and can be cured at lower temperatures, addressing the issues of degradation and high temperature requirements in existing coatings.
Implementation Method 1
at least one moiety comprising a phosphorous acid group, the moiety covalently bonded to the addition polymer backbone by a carbon-carbon bond
Implementation Method 2
electrophoretically depositing a coating formed from the aqueous resinous dispersion onto at least a portion of the substrate
Data Source
AI summary
The present invention is directed to an addition polymer comprising an addition polymer backbone; at least one moiety comprising a phosphorous acid group, the moiety being covalently bonded to the addition polymer backbone by a carbon-carbon bond; and at least one carbamate functional group. The present invention is also directed towards methods of making the addition polymer, aqueous resinous dispersions and electrodepositable coating compositions comprising the addition polymer, methods of coating a substrate and coated substrates.