Self-crosslinking Pigment Dispersion with Tertiary Amine Inhibitor
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Solution Overview
Problem
Existing coatings made with pigmented inks face challenges with wet and dry rub durability due to the short shelf-life of traditional crosslinking formulations, which undergo rapid crosslinking reactions, necessitating a solution for self-crosslinking dispersions that delay crosslinking until exposure to atmosphere and optional heat.
Innovation Solution
A dispersion comprising a pigment, a polymer with carboxyl groups, a crosslinking agent, an inhibition agent (tertiary amine), and a liquid carrier, where the mean particle size and viscosity increase by less than 20% over three months in sealed storage at ambient temperature, facilitating controlled crosslinking after application and exposure to heat or atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional crosslinking formulations are used to improve coating durability, then wet and dry rub durability is improved, but shelf-life is reduced due to rapid crosslinking reaction progression
Solution Approach 1:
The patent applies preliminary action by pre-mixing the crosslinking agent with the pigment dispersion before application, so that the crosslinking components are already in place and will react immediately upon exposure to the atmosphere. This ensures that the crosslinking reaction is prepared in advance but does not occur until the appropriate time, resolving the contradiction between durability improvement and shelf-life maintenance.
Solution Approach 2:
The patent uses the atmosphere (air) as an intermediary to trigger the crosslinking reaction. The crosslinking agent is mixed with the dispersion but remains dormant until exposed to atmospheric conditions, which act as a mediator to initiate the reaction. This allows the formulation to remain stable during storage while enabling rapid crosslinking after application, thus improving both durability and shelf-life.
2Duration of action of stationary object
If crosslinking reaction is delayed until after application, then shelf-life is extended, but crosslinking may not occur sufficiently to provide adequate durability
Solution Approach 1:
The patent applies parameter changes by altering the environmental conditions (exposure to atmosphere and heat) to control the timing and rate of the crosslinking reaction. By changing these parameters after application, the system ensures that crosslinking occurs sufficiently to provide durability while maintaining extended shelf-life during storage. The reaction parameters are optimized to occur rapidly under post-application conditions.
3Reliability
If crosslinking occurs rapidly after application, then coating durability is improved, but particle size and viscosity increase excessively during storage
Solution Approach 1:
The patent uses the atmosphere as an intermediary that triggers the crosslinking reaction only after application. This prevents premature crosslinking during storage, maintaining dispersion stability (particle size and viscosity within acceptable ranges) while enabling rapid crosslinking after application to improve durability. The atmospheric exposure acts as the trigger that separates storage stability from post-application performance.
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 stable dispersions and inks with improved durability by controlling the crosslinking reaction, ensuring the coatings remain stable during storage and undergo significant crosslinking only after application, enhancing their durability and shelf-life.
Implementation Method 1
a crosslinking agent capable of undergoing a crosslinking reaction with the carboxyl group
Implementation Method 2
an inhibition agent comprising a tertiary amine
Implementation Method 3
whereupon the crosslinking agent and the carboxyl group undergo the crosslinking reaction
Data Source
AI summary
A dispersion comprising a pigment, a polymer comprising a carboxyl group, a crosslinking agent capable of undergoing a crosslinking reaction with the carboxyl group, an inhibition agent comprising a tertiary amine, and a liquid carrier, wherein at least one of the mean particle size and the viscosity of the dispersion increases by less than 20% over about three months in sealed storage at ambient temperature, as determined by accelerated shelf life testing.