Epoxy Polysiloxane Oligomers for Flexible Coatings
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Solution Overview
Problem
Existing epoxy-functional silane oligomers in coatings compromise flexibility due to high molecular weight and generate high VOC emissions from partial hydrolysis, necessitating a stable, low or zero VOC epoxy-containing polysiloxane oligomer composition that enhances chemical resistance while maintaining flexibility.
Innovation Solution
A composition comprising specific mole percentages of polysiloxane oligomers of defined formulas, prepared by hydrolyzing a silane in the presence of controlled water and optionally a catalyst, followed by distillation to remove alcohol and condense silanols, resulting in a polysiloxane oligomer with added stabilizing agents to enhance stability and reduce VOC emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight oligomeric epoxy-functional silanes are used to improve chemical resistance, then chemical resistance is improved, but flexibility is compromised
Solution Approach 1:
The patent segments the oligomeric epoxy-functional silane into multiple discrete molecular weight components (monomeric, dimeric, trimeric, tetrameric units) with specific mole percent ranges for each. This segmentation allows optimization of the balance between chemical resistance (provided by higher molecular weight components) and flexibility (provided by lower molecular weight components), resolving the technical contradiction.
2Ease of operation
If monomeric epoxy-functional alkoxysilane is used in coating compositions, then ease of application is improved, but VOC emissions increase due to partial hydrolysis
Solution Approach 1:
The patent performs preliminary hydrolysis and condensation reactions during the manufacturing process to pre-form stable polysiloxane oligomers with specific molecular weight distributions. This preliminary action eliminates the need for further hydrolysis during application, preventing VOC emissions while maintaining ease of application. The product is prepared in advance in its final stable form.
3Ease of manufacture
If low molecular weight epoxy-functional silane oligomers are used to maintain flexibility, then flexibility is improved, but VOC emissions increase due to partial hydrolysis
Solution Approach 1:
The patent performs preliminary condensation reactions during manufacturing to form stable polysiloxane oligomers with low molecular weight components (monomeric, dimeric, trimeric units). These pre-formed oligomers are stable and do not undergo further hydrolysis during application, eliminating VOC emissions while maintaining the flexibility benefits of low molecular weight structures.
4Object-generated harmful factors
If epoxy-containing polysiloxane oligomer composition is designed for zero or low VOC content, then VOC emissions are minimized, but stability and performance may be compromised
Solution Approach 1:
The patent changes the chemical parameters by designing a specific molecular weight distribution profile with defined mole percent ranges for different oligomeric units and selecting specific polysiloxane structures (Formulae I-V). These parameter changes create a stable, zero or low VOC containing composition that maintains both stability and performance.
Solution Approach 2:
The patent creates a composite oligomeric structure comprising multiple different polysiloxane units (Formulae I-V) with specific molecular weight distributions. This composite approach combines the stability benefits of polysiloxane structures with the performance benefits of varied molecular weight components, achieving zero or low VOC content without compromising stability.
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 coatings with high chemical resistance and maintained flexibility, while minimizing VOC emissions, as evidenced by low releasable alcohol content and improved stability over time.
Implementation Method 1
hydrolyzing a silane of the general Formula (VI) in the presence of 2 to 15 moles of water per mole of the silane and, optionally, a hydrolysis catalyst, at a temperature of from 10° to 100° C. to provide an intermediate containing a silanol and an alcohol
Implementation Method 2
removing the alcohol by distillation
Implementation Method 3
removing water to condense the silanol to provide an epoxy-containing polysiloxane oligomer composition
Data Source
AI summary
The present invention relates to stable, zero or low VOC epoxy-containing polysiloxane oligomer compositions that provide for a high degree of chemical resistance to compositions containing organic resins, while at the same time, maintaining or improving the flexibility of these organic resin-containing compositions, to processes for preparing epoxy-containing polysiloxane oligomer compositions, and to uses in coatings, sealants, adhesives, and composites containing the same.