Binder Composition for Catalyst Washcoat Adhesion
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Solution Overview
Problem
Existing catalytic washcoat compositions face challenges in achieving optimal binding strength to substrates without increasing viscosity, which can lead to non-uniform coatings and washcoat loss over time.
Innovation Solution
The use of a binder composition comprising a plurality of binders with differing mean particle sizes in defined ratios, which enhances adhesion and viscoelastic behavior of the washcoat on the substrate without significantly increasing viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the overall binder content in a washcoat composition is increased to enhance binding strength, then the binding strength between washcoat and substrate is improved, but the total viscosity of the composition significantly increases, hindering uniform coating
Solution Approach 1:
The binder content is segmented into two distinct particle size groups: fine particles (0.1-10 μm) and coarse particles (10-100 μm). This segmentation allows the fine particles to provide binding strength while the coarse particles maintain low viscosity, resolving the contradiction between binding strength and viscosity.
Solution Approach 2:
Different particle sizes are assigned different functional roles: fine particles are concentrated at the binder-substrate interface to maximize adhesion, while coarse particles are distributed throughout the washcoat bulk to maintain low viscosity and uniform coating properties. This local quality differentiation resolves the binding strength-viscosity contradiction.
2Object-generated harmful factors
If the overall binder content in a washcoat composition is decreased to reduce viscosity, then uniform coating is improved, but the binding strength of the washcoat to the substrate is reduced, leading to washcoat loss
Solution Approach 1:
The binder population is segmented into fine and coarse particles with distinct functions. The fine particles (0.1-10 μm) are optimized for binding strength at the interface, while coarse particles (10-100 μm) control viscosity. This segmentation allows low overall binder content to achieve both low viscosity and high binding strength.
Solution Approach 2:
The washcoat uses a composite binder system combining two particle size distributions. This composite approach allows the fine particles to provide interfacial adhesion while coarse particles provide bulk viscosity control, achieving both low viscosity and high binding strength simultaneously.
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
This approach allows for increased binder content without viscosity issues, leading to improved washcoat uniformity and durability, thereby enhancing the binding strength and reducing washcoat loss.
Implementation Method 1
the combination of a plurality of binders can improve viscoelastic behavior of the washcoat that is adhered to the substrate therewith
Data Source
AI summary
The present disclosure provides binder compositions formed with a plurality of binder materials having differing mean particles, the binder compositions being useful to improve washcoat adhesion on a substrate. Adhesion can be improved related to an increase in the binder concentration without a significant or substantial increase in associated viscosity. Such binder compositions can comprise a first binder material formed of a plurality of particles having a first mean particle size and a second binder material formed of a plurality of particles having a second mean particle size, wherein a ratio of the first mean particle size to the second mean particle size about 2 or greater. The present disclosure further provides catalyst compositions, catalyst articles, and emission systems incorporating the binder compositions.