Noble Metal Catalyst Stabilization in Silicone Compositions
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Solution Overview
Problem
Existing silicone compositions face challenges with premature crosslinking at room temperature and require complex activation processes, including the use of inhibitors or additional compounds that can affect reactivity and stability, leading to inefficient and costly processing.
Innovation Solution
The development of addition-crosslinking silicone compositions that incorporate a noble metal catalyst in an oxidation state greater than 0, combined with a bidentate chelate ligand that acts as a scavenger to prevent premature crosslinking, allowing for stable storage at room temperature and rapid activation at elevated temperatures or with radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If inhibitors are added to extend pot life at room temperature, then storage stability is improved, but reactivity at higher temperatures decreases and start-up temperature increases
Solution Approach 1:
A silicon-bound inhibitor is used as an intermediary that selectively binds to the platinum catalyst at room temperature to prevent premature crosslinking, but releases it at elevated temperatures to enable rapid curing. This mediator resolves the contradiction by providing temperature-dependent control of catalyst activity.
Solution Approach 2:
The invention changes the temperature parameter to control the inhibitor-catalyst interaction. At room temperature, the inhibitor binds to the catalyst to stabilize the composition. At elevated temperatures, the inhibitor releases the catalyst to enable rapid crosslinking. This parameter change resolves the contradiction between storage stability and reactivity.
2Productivity
If Pt(0) complexes are used for high reactivity at room temperature, then crosslinking speed is improved, but premature crosslinking occurs and pot life is reduced
Solution Approach 1:
The silicon-bound inhibitor applies preliminary anti-action by binding to the Pt(0) catalyst at room temperature to prevent premature crosslinking and extend pot life. When heated, the inhibitor releases the catalyst, allowing rapid crosslinking to proceed. This preliminary protective action resolves the contradiction between crosslinking speed and pot life.
3Reliability
If thermal activation is used for crosslinking, then catalyst activation is achieved, but energy consumption and processing cost increase
Solution Approach 1:
The composition is prepared in advance with the platinum catalyst and silicon-bound inhibitor already combined, but the crosslinking reaction is preliminarily prevented from occurring at room temperature. This preliminary preparation allows the system to be ready for rapid activation when heated, reducing the actual processing time and energy consumption during the crosslinking step.
4Stability of the object's composition
If multiple components are used to achieve stable storage and controlled curing, then storage stability is improved, but system complexity increases
Solution Approach 1:
The invention merges the inhibitor and catalyst into a single silicon-bound inhibitor complex, eliminating the need for separate inhibitor and catalyst components. This unified approach maintains storage stability while simplifying the system to a true one-component formulation that requires no mixing or additional processing steps.
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 enables one-component silicone compositions with extended pot life and rapid polymerization upon thermal or radiation-induced activation, maintaining stability and efficiency while simplifying the processing and reducing material costs.
Implementation Method 1
The invention uses a chelating ligand with at least bidentate ligand that binds to the noble metal catalyst to form a stable complex, preventing premature crosslinking at room temperature
Implementation Method 2
In addition-curing silicone compounds, the crosslinking process generally occurs via a hydrosilylation reaction, in which platinum or another platinum group metal is typically used as a catalyst
Implementation Method 3
Structurally diverse catalysts are known in the art. They are typically activated either thermally or by ultraviolet and/or visible radiation
Data Source
AI summary
The invention relates to a novel method for stabilizing noble metal catalysts. The invention particularly relates to the domain of addition-curing silicone compositions that are activated by heat, UV and/or visible radiation, the production thereof, the use thereof in crosslinkable compositions and to crosslinked products obtained therefrom.