Partially-Fluorinated Silanes for Fluoropolymer-Silicone Bonding
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Solution Overview
Problem
Satisfactory bonding of fluoropolymers to other polymers, particularly silicones, is often difficult, especially after prolonged exposure at elevated temperatures, which complicates the creation of reliable multi-layer articles like hoses that require chemical resistance.
Innovation Solution
The development of functional, partially-fluorinated silane compounds, which are synthesized through a method involving a partially-fluorinated dialkene and trichlorosilane using a platinum catalyst, followed by reaction with an alcohol to produce trialkoxy silanes, are used as bonding agents between fluoropolymer and silicone polymer compositions, enhancing their adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluoropolymer and silicone polymer are bonded directly, then the bonding process is simple, but the bond strength deteriorates after prolonged exposure at elevated temperatures
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the fluoropolymer and silicone polymer. The silane compound contains both fluorinated groups that interact with the fluoropolymer and silane groups that bond with the silicone polymer, creating a stable intermediate layer that maintains bond strength at elevated temperatures while keeping the overall bonding process relatively simple
2Reliability
If a bonding agent is used between fluoropolymer and silicone polymer, then the bond strength at elevated temperatures is improved, but the manufacturing complexity increases
Solution Approach 1:
The silane coupling agent is designed with specific molecular parameters including fluorinated alkyl chains with 1-8 carbon atoms and silane functional groups that can be adjusted by changing the number of alkoxy groups (1-4). This parameter optimization allows the bonding agent to provide excellent high-temperature bond strength while maintaining ease of application and processing
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
These silane compounds improve the bond strength between fluoropolymer and silicone compositions, ensuring a strong and reliable interface even after thermal aging, thus addressing the challenge of bonding fluoropolymers to silicones at elevated temperatures.
Implementation Method 1
monohydrosilylating the partially-fluorinated dialkene with trichlorosilane using a platinum catalyst to form a functional, partially-fluorinated, trichlorosilane compound
Implementation Method 2
These silane compounds improve the bond strength between fluoropolymer and silicone compositions, ensuring a strong and reliable interface
Data Source
AI summary
Functional, partially-fluorinated silane compound according to Formula (I): wherein: X is CH2=CH— or CHCH2—; R1 and R2 are linear or branched alkylenes having 1 to 4 carbon atoms; Rf is a perfluoro(alkylene) group having 1 to 8 carbon atoms and, optionally, at least one catenary heteroatom selected from the group consisting of O and N; c is equal to the number of carbon atoms in X; and Y is —Cl or —OR, wherein R is a linear or branched alkyl having 1 to 4 carbon atoms. In some embodiments, Y is —O(CH2)xCH3 wherein x is an integer from 0 to 3 are described. Methods of making and using such functional, partially-fluorinated silane compounds are also described