Pre-conversion Coating Composition for Automotive Corrosion Protection
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Solution Overview
Problem
Automotive vehicle components, such as body panels, are susceptible to corrosion due to the lack of protective coatings during shipping and assembly, leading to black spot corrosion.
Innovation Solution
A coating composition comprising a corrosion inhibitor and calcium phosphate or the reaction product of a calcium compound with an acid is applied to the substrate, followed by dehydration and optional rinsing or removal of the coating layer, allowing for the application of a second coating composition to enhance corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no protective coating is applied to metal components during shipping and assembly, then the components remain uncoated and can be easily handled, but they become susceptible to corrosion and black spot formation
Solution Approach 1:
The patent applies a pre-conversion coating containing calcium phosphate and corrosion inhibitors to metal substrates before the main conversion coating process. This preliminary coating establishes initial corrosion protection and prepares the surface for subsequent coating steps, preventing black spot corrosion during shipping and assembly operations.
Solution Approach 2:
The pre-conversion coating combines calcium phosphate with specific corrosion inhibitors (such as benzotriazole, tolyltriazole, or their derivatives) to create a composite coating system. This composite approach provides synergistic corrosion protection that is more effective than either component alone, while maintaining process simplicity.
2Duration of action of stationary object
If a pre-conversion coating with calcium phosphate and corrosion inhibitors is applied before conversion coating, then corrosion protection time is extended, but the coating process becomes more complex with additional steps
Solution Approach 1:
The pre-conversion coating is applied and allowed to dry or partially cure before the main conversion coating is applied. This preliminary action extends the effective corrosion protection period during shipping and assembly, and the process is integrated into existing conversion coating lines without requiring completely new equipment.
Solution Approach 2:
The patent maintains continuous corrosion protection throughout the coating process by applying the pre-conversion coating, allowing it to establish protective properties, then immediately applying the conversion coating over it. This continuous approach ensures uninterrupted corrosion protection while extending the duration before black spot corrosion occurs.
3Reliability
If traditional single-stage conversion coating is used, then the process is simple and fast, but corrosion protection is insufficient and black spots appear quickly
Solution Approach 1:
The coating process is segmented into two distinct stages: a pre-conversion coating stage with calcium phosphate and corrosion inhibitors, followed by a main conversion coating stage. This segmentation allows each coating to perform its specific function optimally, extending the time before black spot corrosion appears compared to single-stage processes.
Solution Approach 2:
The pre-conversion coating uses a composite formulation of calcium phosphate with specific corrosion inhibitors (benzotriazole, tolyltriazole, or their derivatives). This composite material provides enhanced and extended corrosion protection, delaying black spot appearance longer than traditional single-material conversion coatings.
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 described coating system effectively inhibits corrosion on metal substrates, extending the time before black spot corrosion appears, as demonstrated by increased resistance in corrosion testing.
Implementation Method 1
a coating composition comprising (i) a corrosion inhibitor and (ii) calcium phosphate
Implementation Method 2
dehydrating at least a portion of the first coating composition thereby forming a first coating layer
Data Source
AI summary
The present invention is directed to a coating composition comprising (i) a corrosion inhibitor and the (ii) reaction product of a calcium compound with an acid compound. The coating composition is deposited onto a substrate prior to the application of a pre-treatment coating composition (conversion coating) onto the substrate. The present invention is also directed to a substrate that comprises a coating system that comprises such a coating composition.