Liquid Coating Composition with Immobilized Catalyst
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Solution Overview
Problem
Existing liquid coating compositions with polyurethane resin and cure catalysts face challenges in achieving effective crosslinking due to the catalyst's immobilization in the resin, which limits their catalytic activity at room temperature, and the need for improved storage stability and curing conditions.
Innovation Solution
A liquid coating composition comprising a resin system crosslinkable under catalysis, with a physical mixture of 70-99 wt.% polyurethane resin and 1-30 wt.% immobilized catalyst, allowing for thermal activation of the catalyst above the resin's melting temperature, enabling efficient crosslinking reactions while maintaining storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the catalyst is immobilized in the polyurethane resin, then storage stability is improved, but catalytic activity at room temperature deteriorates
Solution Approach 1:
The patent applies parameter changes by utilizing the melting temperature of the polyurethane resin as a threshold to activate the catalyst. Below the melting temperature, the catalyst remains immobilized and inactive, ensuring storage stability. Above the melting temperature, the resin melts and releases the catalyst, activating it for crosslinking reactions. This temperature-dependent parameter change resolves the contradiction between stability and activity.
Solution Approach 2:
The patent employs phase transitions of the polyurethane resin (solid to liquid upon melting) to control catalyst availability. In the solid state below melting temperature, the catalyst is trapped in the resin matrix, providing stability. Upon heating above the melting temperature, the resin transitions to liquid state, releasing the catalyst for active crosslinking. This phase transition mechanism simultaneously achieves both storage stability and catalytic activity.
2Stability of the object's composition
If the catalyst is immobilized in the polyurethane resin, then storage stability is improved, but curing temperature requirement worsens
Solution Approach 1:
The patent uses the melting temperature parameter of the polyurethane resin as a trigger. By designing the resin to melt at a specific temperature range, the system automatically activates the catalyst at that temperature threshold, enabling curing to occur at lower temperatures than would otherwise be required to activate an immobilized catalyst.
Solution Approach 2:
The phase transition (melting) of the polyurethane resin serves dual purposes: it provides thermal energy to initiate curing while simultaneously releasing the trapped catalyst. This eliminates the need for separate high-temperature treatment to activate the catalyst, thereby reducing the overall curing temperature requirement while maintaining storage stability at lower temperatures.
3Reliability
If the polyurethane resin is used as a binder, then coating performance is improved, but crosslinking efficiency deteriorates due to catalyst immobilization
Solution Approach 1:
The patent introduces dynamic behavior to the otherwise static system. The catalyst transitions from a fixed, immobilized state during storage to an active, mobile state during curing when the resin melts. This dynamic transformation allows the system to maintain both the protective properties of the immobilized catalyst during storage and the high crosslinking efficiency of an active catalyst during the curing process.
Solution Approach 2:
The phase transition of the polyurethane resin from solid to liquid state enables the catalyst to transition from an inactive immobilized form to an active catalytic form. This phase change ensures that the coating achieves full crosslinking efficiency during curing while maintaining the benefits of catalyst immobilization during storage, thus resolving the contradiction between coating performance and crosslinking efficiency.
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 effective crosslinking at elevated temperatures, enhancing the coating's properties and reducing the required curing temperature, while maintaining unimpaired storage stability and pot life, suitable for single-layer or multilayer coatings.
Implementation Method 1
the polyurethane resin C has a melting temperature of 40 to 180° C., in particular, 60 to 160° C., measured by DSC (differential scanning calorimetry) at a heating rate of 10 K/min
Implementation Method 2
a resin system crosslinkable under the catalysis of a catalyst D and comprising a binder A and, as an optional component, a crosslinker B for the binder A
Data Source
AI summary
A liquid coating composition which contains (i) a resin system crosslinkable under catalysis of a catalyst D and comprising a binder A and, as an optional component, a crosslinker B for the binder A, and (ii) solid particles CD consisting of a physical mixture of 70 to 99 wt.-% of a polyurethane resin C and 1 to 30 wt.-% of a catalyst D immobilized in said polyurethane resin C, wherein the sum of the wt.-% totals 100 wt.-%, and wherein the polyurethane resin C has a melting temperature of 40 to 180° C., measured by DSC at a heating rate of 10 K/min.