Electrodepositable Coating Viscosity Control
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Solution Overview
Problem
Electrodepositable coating compositions with high pigment levels often experience sedimentation and uneven coatings, leading to poor appearance and corrosion protection issues.
Innovation Solution
An electrodepositable coating composition with a resin solids content of less than 30% by weight and a viscosity of at least 15 cP at a shear rate of 0.1/s, containing an ionic salt group-containing film-forming polymer and a curing agent, along with a pigment-to-binder ratio of less than 0.2:1, optionally including a phyllosilicate pigment and a pigment dispersing acid, to prevent sedimentation and ensure smooth coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high pigment levels are used in electrodepositable coating compositions, then paint utilization and corrosion protection are improved, but sedimentation and uneven coatings occur leading to poor appearance
Solution Approach 1:
The patent changes the viscosity parameter of the coating composition to at least 15 cP at a shear rate of 0.1/s, which prevents pigment sedimentation and ensures uniform coating deposition. This parameter adjustment allows high pigment levels (up to 50% by weight) to be maintained without compromising coating uniformity or causing sedimentation issues.
2Reliability
If high pigment levels are used in electrodepositable coating compositions, then corrosion protection is improved, but sedimentation occurs
Solution Approach 1:
By adjusting the viscosity parameter to at least 15 cP at a shear rate of 0.1/s, the patent stabilizes the coating composition and prevents pigment sedimentation. This enables the use of high pigment levels (up to 50% by weight) while maintaining composition stability and preventing sedimentation, thereby ensuring reliable corrosion protection.
3Loss of substance
If resin solids content is reduced to improve paint utilization, then environmental contamination is reduced, but coating performance may be compromised
Solution Approach 1:
The patent changes the viscosity parameter to at least 15 cP at a shear rate of 0.1/s, which allows the coating to achieve proper film formation and corrosion protection even with reduced resin solids content (less than 30% by weight). This parameter adjustment enables improved paint utilization while maintaining coating performance through optimized flow and deposition characteristics.
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 composition achieves a smooth, even coating with improved corrosion protection and reduced sedimentation, resulting in a surface roughness of less than 90 microinches and enhanced paint utilization.
Implementation Method 1
Electrodeposition as a coating application method involves deposition of a film-forming composition onto a conductive substrate under the influence of an applied electrical potential
Implementation Method 2
an electrodepositable binder comprising an ionic salt group-containing film-forming polymer and a curing agent
Data Source
AI summary
The present disclosure is directed to an electrodepositable coating composition comprising an electrodepositable binder comprising an ionic salt group-containing film-forming polymer and a curing agent; and at least one pigment: wherein the electrodepositable coating composition has a resin solids content of less than 30% by weight, based on the total weight of the electrodepositable coating composition, and a viscosity of at least 15 cP at a shear rate of 0.1/s, as measured by the BATH VISCOSITY TEST METHOD; and wherein the pigment optionally comprises a phyllosilicate pigment, and the pigment-to-binder ratio of the phyllosilicate pigment to the electrodepositable binder is less than 0.2:1 if the electrodepositable coating composition is a cationic electrodepositable coating composition and a pigment dispersing acid is present in the cationic electrodepositable coating composition. Also disclosed are coatings, coated substrates, and methods of coating a substrate.